ELECTRICAL MACHINE WITH SEVERAL RIGID WINDING PIECES DESIGNED AS WAVEGUIDES

Description

[0001] The invention relates to an electrical machine having a rotor, a stator and a plurality of winding pieces designed as waveguides, which form different coils of a winding of the electrical machine and are each part of a cooling circuit of the electrical machine. HINTERGRUND DER ERFINDUNG

[0002] Internally cooled electrical machines are known from the prior art, with windings manufactured using so-called pin or hairpin technology. Pins or hairpins are rigid winding pieces, usually made of copper, that are inserted into slots in the stator of the electrical machine and generate a magnetic field during operation. In internally cooled electrical machines, the winding pieces are designed as waveguides, which include a continuous channel through which a coolant is conducted to cool the electrical machine.

[0003] Rigid winding pieces known from the prior art are usually in the shape of hairpins or rods. For example, hairpins comprise two essentially parallel legs and a curved transition area connecting the two legs. These winding pieces are usually provided with an electrically insulating layer on their outer surface.

[0004] DE 195 02 308 A1, for example, shows an electrical machine with a rotor, a stator, and several winding sections designed as waveguides. Furthermore, a hydraulic connection part with connections for a plurality of winding sections is provided, to which the end sections of the winding sections are hydraulically connected, as well as a seal having several passages, in each of which an end section of one of the winding sections is arranged. However, the connection part shown in DE 195 02 308 A1 only allows the simultaneous hydraulic connection of all winding sections to the same coolant circuit. Furthermore, the connection part is relatively difficult to seal. Other electrical machines with an internally cooled winding are known from WO 2018 / 033 307 A1 and DE 696 06 967 T2.

[0005] DE 19 13 219 A1 further describes an electrical machine with a waveguide winding and a special connection device to which the ends of the waveguides are hydraulically connected. The connection device comprises a hydraulic connection part and a seal through which the end sections of the waveguides are passed. Further electrical machines with an internally cooled waveguide winding and a connection device for hydraulically connecting the waveguides are known from US Pat. No. 5,875,539 A, DE 24 16 965 A1, and DE 10 89 057 B.

[0006] In such electrical machines with a waveguide winding formed from rigid winding pieces, the hydraulic connection of the individual winding pieces can be further simplified. OBJECT OF THE INVENTION

[0007] It is therefore an object of the present invention to provide an electrical machine with a waveguide winding formed from a plurality of rigid winding pieces, which is particularly simple in construction, in particular with regard to the hydraulic connection of the individual winding pieces.

[0008] This object is achieved according to the invention by the features stated in independent claim 1. Further embodiments of the invention emerge from the subclaims.

[0009] According to the invention, an electrical machine is proposed which comprises a rotor, a stator, a plurality of external phase connections, and a plurality of winding pieces designed as waveguides, which form different coils of a winding of the electrical machine and are each part of a cooling circuit of the electrical machine. The electrical machine according to the invention further comprises a hydraulic connection part with connections for a plurality of winding pieces, to which the end sections of the winding pieces are hydraulically connected, as well as a seal which has a plurality of passages, in each of which an end section of one of the winding pieces is arranged, wherein the hydraulic connection part and the seal have opposing surfaces which lie on one another or are pressed against one another in order to ensure a seal between the individual connections of the winding pieces and the hydraulic connection part.

[0010] The electrical machine according to the invention preferably comprises fastening means for firmly pressing the hydraulic connection part and the seal against each other. The fastening means can comprise, for example, one or more screws. The seal and the hydraulic connection part preferably each have a sealing surface facing in the axial direction of the electrical machine. In this case, the two elements are pressed against each other in the axial direction to seal the hydraulic connection of the winding pieces.

[0011] The hydraulic connection part is designed as a ring-shaped hydraulic connection ring. This allows it to be arranged around the rotor, making the electric machine particularly compact. The seal is also an annular element.

[0012] According to a preferred embodiment of the invention, the hydraulic connection part is designed such that winding sections of coils assigned to different electrical phases (U, V, W) are electrically insulated from one another. Thus, winding sections of different electrical phases can be connected to the hydraulic connection part.

[0013] The individual connections of the hydraulic connection part can be designed to accommodate either a single or multiple winding pieces.

[0014] According to the invention, the hydraulic connection part comprises at least one circumferential channel which is fluidically connected to several of the winding pieces and via which a coolant can be fed into the individual winding pieces or a coolant emerging from the winding pieces can be collected.

[0015] The at least one channel provided in the connecting part is designed as a circumferential groove. The groove is preferably open toward the seal and is covered by the seal when assembled.

[0016] The hydraulic connection part is preferably designed in such a way that all winding pieces are hydraulically connected in parallel.

[0017] The hydraulic connector can be made of plastic, for example, or metal. Electrical insulation elements can be provided to electrically insulate the connected winding sections from the hydraulic connector.

[0018] According to a preferred embodiment of the invention, electrical insulation is achieved by arranging the ends of the rigid winding pieces at a distance from the hydraulic connection part, thus leaving a free space between each winding piece and the hydraulic connection part. An additional insulator is not required in this case, but could still be provided.

[0019] The aforementioned clearance can be created, for example, by having the connection openings provided in the hydraulic connection part with a larger cross-section than the end sections of the individual winding sections. The end sections of the winding sections then protrude into the respective connection without touching the hydraulic connection part. Alternatively, the individual winding sections can also be arranged so that they end at an axial distance from the hydraulic connection part.

[0020] According to a preferred embodiment of the invention, the seal is made of a potting compound that is poured into a space in which the end sections of the winding pieces are arranged when the electrical machine is partially assembled. The potting compound then spreads around the end sections and hardens. In this case, the end sections of the individual winding pieces preferably extend through the seal and protrude towards the hydraulic connection part. The hydraulic connection part can now be placed onto the end sections. In the assembled state, the opposite sides of the seal and the hydraulic connection part rest firmly on one another, thereby ensuring a seal between the hydraulic connections of the winding pieces and the hydraulic connection part.

[0021] The individual winding pieces are preferably open at their front ends so that the coolant is fed in at one end and discharged at the other end.

[0022] In an electrical machine according to the invention, the end sections of the individual winding pieces are preferably arranged in several rows with different radii. They preferably end at approximately the same axial height, i.e., in one axial plane. This makes the electrical machine particularly easy to assemble.

[0023] The aforementioned hydraulic connection part preferably comprises a plurality of circumferential channels for distributing or collecting coolant into or from the individual winding sections. At least one of these channels is preferably designed to fluidically communicate with at least two rows of the end sections of the winding sections.

[0024] The end sections of the individual winding pieces are preferably arranged such that they extend through the seal, protruding toward the hydraulic connection part and each extending into a connection opening of the hydraulic connection part. A connection or connection opening can be designed to accommodate a single or multiple end sections of winding pieces.

[0025] Furthermore, the passages provided in the seal are preferably designed so that the end sections of the winding pieces are tightly received therein.

[0026] The end sections of the winding pieces can also be glued in the seal or in the hydraulic connection part.

[0027] Also disclosed is a method for hydraulically connecting a plurality of rigid winding sections of an electrical machine, designed as waveguides, to a hydraulic connecting part which has a plurality of connections for end sections of the winding sections, the method comprising the following steps: arranging the end sections in a space, filling the space with a potting compound which flows around the end sections of the winding sections and hardens after some time to form a seal, the amount of potting compound being such that the end sections protrude from the seal, and placing the hydraulic connecting part onto the seal such that the projecting end sections dip into the connection openings of the hydraulic connecting part and that opposing surfaces of the hydraulic connecting part and the seal are pressed against one another in order to seal the hydraulic connections of the winding sections.

[0028] If necessary, an additional seal can be inserted between the hydraulic connection part and the seal.

[0029] An electrical machine according to the invention preferably also comprises a plurality of contact rings, each of which is designed to electrically connect a plurality of the winding sections to one of the external phase connections. With the aid of the aforementioned contact rings, it is particularly easy to contact the relevant connections of the coils or winding sections and to connect them to the respective associated external phase connection. This is particularly advantageous for electrical machines that have a plurality of coils connected in parallel per phase (U, V, W), i.e., in which a plurality of coils connected in parallel are assigned to each electrical phase or each external phase connection.

[0030] According to a preferred embodiment of the invention, a contact ring comprises a plurality of terminals for electrically contacting winding pieces, wherein these terminals are preferably evenly distributed over the circumference of the contact ring.

[0031] According to a preferred embodiment of the invention, the electrical machine also comprises a set of several distribution elements, each of which is electrically connected to one of the associated external phase terminals.

[0032] Each of the distribution elements is preferably electrically connected to one of the aforementioned contact rings via a plurality of electrical connecting elements. In this case, such an electrical machine comprises: a set of distribution elements, each of which distributes the current flowing via the external phase terminals to a plurality of electrical connecting elements; said electrical connecting elements, which electrically connect the distribution elements and the contact rings; and said contact rings, each of which contacts a predetermined number of coils connected in parallel. Starting from the external phase terminals (L1, L2, L3), the current path in this case leads via a distribution element, a plurality of electrical connecting elements, and one of the contact rings to the coils of the winding and then on to a reference potential (e.g., the neutral point or another phase).

[0033] The aforementioned electrical connecting elements can, for example, be designed as rod-shaped elements. The connecting elements preferably extend approximately in the axial direction of the electrical machine. They are also preferably distributed evenly around the circumference of the electrical machine.

[0034] The individual distribution elements preferably have different diameters, which simplifies the design of the electrical circuitry. The distribution elements are preferably designed as annular distribution rings.

[0035] The contact and / or distribution elements are preferably arranged next to one another in the axial direction of the electrical machine.

[0036] According to the invention, a winding section designed as a waveguide can, for example, have the shape of a rod. According to another embodiment of the invention, a winding section has the shape of a hairpin, wherein the winding section comprises two legs and a curved transition region that connects the two legs. The two legs are arranged essentially parallel and preferably each have a profile that is adapted to the cross-section of the associated slot in the stator. A winding section according to the invention can, in principle, be dimensioned such that it fills a slot alone or together with one or more additional winding sections.

[0037] A winding piece according to the invention is preferably made of copper, aluminum, or an alloy of one of the aforementioned materials. An electrically insulating layer is preferably provided on its outer surface.

[0038] The individual coils of the winding are preferably formed from several rigid winding pieces that are electrically connected in series.

[0039] The aforementioned distribution elements, the contact rings, and the electrical connecting elements arranged between the distribution elements and the contact rings may have to carry very high current densities. To improve the cooling of these components, a specific embodiment of the invention provides for the configuration of the distribution elements and / or the contact rings and / or the connecting elements, in addition to the winding, as waveguides, so that a coolant can be conducted through these components. The distribution elements, the contact rings, and / or the connecting elements thus themselves form part of the cooling circuit of the electrical machine, allowing it to be cooled particularly effectively.

[0040] As an alternative to the internal cooling described above, the components mentioned can also be cooled externally. For example, the components can be arranged in one or more chambers through which a coolant is passed.

[0041] In principle, any component subject to high thermal stress can be cooled by appropriately routing or designing the coolant path. With a waveguide design, the individual components can be cooled from the inside. Alternatively, the coolant can also be routed externally to cool the component in question. The type of cooling depends on the technical requirements and can be easily implemented by a specialist using practical considerations.

[0042] According to a preferred embodiment of the invention, the contact rings each have a plurality of arms, to each of which at least one of the winding pieces is electrically contacted.

[0043] The contact rings mentioned above can, as mentioned, be made of solid metal. According to another embodiment of the invention, the contact rings are made of a printed circuit board material comprising conductor tracks that electrically contact individual winding pieces.

[0044] The same or possibly other circuit boards can also be provided to electrically connect several winding pieces in series to form the coils of the electrical winding.

[0045] An electrical machine according to the invention can also have at least one contact disk having a plurality of through-openings through which the individual winding pieces are inserted, wherein the contact disk further comprises electrical connectors via which certain winding pieces are electrically connected in series to form the coils of the electrical winding.

[0046] The electrical and hydraulic connections of the individual winding sections are preferably made on only one side of the electrical machine. In the case of bar-shaped winding sections, however, the electrical and / or hydraulic connections of the individual winding sections can also be made on two sides of the electrical machine.

[0047] According to a preferred embodiment of the invention, the end sections of the individual winding pieces are preferably arranged in several, particularly circular, rows. The end sections are preferably arranged in parallel and preferably all point in the axial direction of the electrical machine. The end sections preferably end at approximately the same axial height, i.e., approximately in the same plane. This significantly simplifies the electrical and hydraulic connection of the winding pieces.

[0048] The contact rings and / or the distribution elements are preferably disc-shaped. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The invention is explained in more detail below with reference to the accompanying drawings. They show: Fig. 1 a sectional view of an electrical machine with solid metal contact rings according to a first embodiment of the invention; Fig. 2 a perspective view of a winding piece of an electrical machine in the form of a hairpin; Fig. 3a, 3b various views of an arrangement of several distribution elements for dividing the current fed into the external phase terminals; Fig. 4a bis 4c Contact rings of the individual phases of an electrical machine according to the invention; Fig. 5 a composite contact ring arrangement of the contact rings of the Fig. 4a - 4c ; Fig. 6a, 6b various views of a hydraulic connection part according to a first embodiment of the invention; Fig. 7 a sectional view of a hydraulic connector and a seal according to a specific embodiment of the invention; Fig. 8 a sectional view of an electrical machine with electrical contact rings in the form of printed circuit boards according to a second embodiment of the invention; Fig. 9a - 9d various printed circuit boards of an electrical machine, which serve as contact rings for electrically contacting certain winding pieces of the winding of the electrical machine; and Fig. 10 a perspective view of an electrical contact arrangement comprising the distribution elements of the Fig. 3a, 3b as well as the circuit boards shown in Figures 8a - 8d.

[0050] Fig. 1 shows a sectional view of an electrical machine 1 with a stator 2, a rotor 3, and a winding 4 formed from several rigid winding pieces 5. The rigid winding pieces 5 are designed as waveguides and comprise a continuous channel 9 through which a coolant is conducted to cool the electrical machine 1. The individual winding pieces 5 are hydraulically connected in parallel and each form part of a cooling circuit of the electrical machine 1.

[0051] In the example of Fig. 1 The winding pieces 5 are each arranged individually in slots 24 of the stator 2 of the electrical machine 1. The cross-section of the winding pieces 5 is adapted to the cross-section of the slots 24, so that they are accommodated in the slots 24 essentially without play. Alternatively, more than one winding piece 5 could be provided per slot 24.

[0052] As a coolant, for example, oil, Therminol, Galden or carbon dioxide can be used.

[0053] The electrical machine 1 further comprises a housing 13 with a housing cover 17 in which all components of the electrical and hydraulic connection arrangement are accommodated.

[0054] Furthermore, fastening elements 47 are provided, here in the form of screws, with which the housing is screwed together. The electric machine is designed such that tightening the fastening elements simultaneously presses a hydraulic connection part 15 against a seal 27. The structure and function of these components will be explained in more detail below.

[0055] At the Fig. 1 In the electrical machine 1 shown, the winding pieces 5 are designed as so-called hairpins, as they are shown, for example, in Fig. 2 are shown. The Fig. 2 The winding section 5 shown comprises two essentially parallel legs 6 and a curved transition region 10 that connects the two legs 6 to one another. The hairpin shown is designed as a waveguide and comprises a continuous channel 9 that extends from one end section 8 to the other end section 8 and through which a coolant is conducted to cool the winding 4 of the electrical machine 1 during operation. The hairpin is open at each of its front ends 33. One of the front ends 33 can thus be used as a coolant inlet and the other front end 33 as a coolant outlet.

[0056] The Fig. 2 The winding piece 5 shown can be made of copper, for example. Its outer surface is preferably provided with an electrically insulating layer.

[0057] The winding section 5 can, for example, have a round or square profile. The winding section 5 can also have a different profile at different sections. According to a preferred embodiment, the profile is round at the end sections.

[0058] The Fig. 1 The electrical machine 1 shown is three-phase and accordingly has three external phase connections L1, L2 and L3, to which the electrical phases U, V and W are connected. The winding 4 of the electrical machine 1 is designed here such that it comprises a plurality of coils connected in parallel for each electrical phase U, V and W. The individual winding pieces 5 are electrically connected such that a plurality of winding pieces are connected in series to form a coil, and a plurality of such coils belonging to the same electrical phase U, V, W are connected in parallel. According to a special embodiment of the invention, each phase U, V, W can comprise, for example, eight parallel coils. The winding 4 of the electrical machine can of course also have coils connected in more or fewer parallel configurations.

[0059] The end sections 8 of those winding pieces 5 which are at the phase potential U, V, W are connected to the respective external phase connection L1, L2 or L3 via an electrical contact arrangement, which will be discussed in more detail below.

[0060] In this embodiment, the electrical contact arrangement comprises a set of three distributor elements 11a, 11b, 11c, as shown by way of example in the Figuren 3a, 3b Each of the distribution elements 11a, 11b, 11c is electrically connected to one of the external phase terminals L1, L2, L3. In the illustrated embodiment, the distribution element 11a is electrically connected to the phase terminal L1, the distribution element 11b is electrically connected to the phase terminal L2, and the distribution element 11c is electrically connected to the phase terminal L3. The three distribution elements 11a to 11c are arranged next to one another in the axial direction B of the electrical machine 1 and are electrically insulated from one another.

[0061] Each distribution element 11a, 11b, 11c further comprises a plurality of receptacles 45 for electrical connecting elements 12a-12d, which are preferably evenly distributed over the circumference of the distribution element. The individual distribution elements 11a, 11b, 11c essentially serve to distribute the current supplied to the phase terminals L1, L2, L3 over the circumference of the electrical machine 1 and to conduct it to the downstream contact rings 18a-18d. Each of the distribution elements 11a-11d is electrically connected to a respective contact ring 18a-18d via a plurality of electrical connecting elements 12a-12d.

[0062] The Figuren 4a - 4c show various contact rings 18a-18c according to a specific embodiment of the invention. Contact ring 18a is electrically connected to the associated distribution element 11a and phase terminal L1, contact ring 18b is electrically connected to the associated distribution element 11b and phase terminal L2, and contact ring 18c is electrically connected to the associated distribution element 11c and phase terminal L3.

[0063] As in the Figuren 4a - 4c As can be seen, the electrical connecting elements 12a-12c are each attached to the associated contact rings 18a-18c and are evenly distributed over the circumference of the contact rings 18a-18c. In the assembled state, the contact rings 18a-18c are positioned substantially transversely to the axial direction B of the electrical machine 1, and the electrical connecting elements 12a-12c extend substantially in the axial direction B.

[0064] Each of the electrical contact rings 18a-18c comprises a plurality of arms 23 for electrically contacting end sections 8 of those development pieces 5 that are connected to a specific electrical phase U, V, or W. In the present exemplary embodiment, each contact ring 18a-18c comprises eight arms 23 for contacting one of eight winding pieces 5 of eight parallel-connected coils. The arms 23 have different lengths in order to contact radially more inward or more outward end sections 8 of the winding pieces 5. Each arm 23 comprises a contact opening 16 through which the end section 8 of a winding piece 5 is inserted and soldered in place.

[0065] In an electrical machine 1 according to the invention, the end sections 8 of the individual winding sections 5 are preferably arranged in several, particularly circular, rows. The end sections 8 of the winding sections 5 are preferably arranged parallel to one another and preferably all point in the axial direction B. The end sections 8 preferably all end at the same axial height, i.e., approximately in the same plane. This facilitates the electrical contacting of the individual winding sections 5 and their hydraulic connection to the cooling circuit.

[0066] Fig. 5 shows the contact rings 18a - 18c of the Fig. 4a - 4c in an assembled state. As can be seen, the individual contact rings 18a - 18c are arranged next to one another in the axial direction B of the electrical machine 1 and are electrically insulated from one another.

[0067] In addition to the electrical connection of individual winding sections 5 to the respective external phase connection L1, L2, L3, it is also necessary to connect certain winding sections 5 in series to form the coils of the winding 4 of the electrical machine 1. For the purpose of serial connection, simple electrical conductors can be used, for example, which are soldered between the desired winding sections.

[0068] According to a preferred embodiment of the invention, however, an electrical contact disk 39 with electrical connectors 40 is provided, as shown in Fig. 13. Before referring to this contact disk 39, the hydraulic connection of the individual winding pieces 5 will first be discussed below: Fig. 6a und 6b show various perspective views of a hydraulic connection part 15, to which all winding pieces 5 are hydraulically connected. The hydraulic connection part 15 comprises a plurality of connections or connection openings 46, which are designed here as circumferential channels 31 and 32, respectively, which are each fluidically connected to a plurality of the winding pieces 5 and through which a coolant is fed into the winding pieces 5 or a coolant escaping from the winding pieces 5 is collected.

[0069] The central channel 32 of the hydraulic connection part 15 is wider than the other two channels 31 and spans two adjacent annular rows of end sections 8. The other two channels 31, one of which is arranged radially outside and one radially inside the central channel 32, are each assigned to a single annular row of end sections 8. All channels 31, 32 extend essentially over the entire circumference of the hydraulic connection part 15.

[0070] In the present case, the coolant is fed into the connected winding sections 5 via the central channel 32 and exits at the other end of the winding sections 5 either into the outer or inner channel 31. Various passages 26 are provided in the area of ​​the central channel 32, through which the coolant enters the channel 32. Furthermore, several passages 44 are provided in the area of ​​the outer channel 31, through which the coolant exits the hydraulic connection part 15. Additional inlet or outlet openings can also be provided on the circumferential surface of the hydraulic connection part 15.

[0071] The hydraulic connection part 15 further comprises a plurality of passages 25 through which the connecting elements 12a - 12c are inserted between the contact rings 18a - 18c and the distributor elements 11a - 11c.

[0072] As in the Fig. 6a und 6b As can be seen, the individual channels 31, 32 are designed as annular grooves, which are arranged in a surface of the hydraulic connection part 15 facing in the direction of the contact rings 18a - 18d. In the first embodiment of the electrical machine 1 of Fig. 1 The end sections 8 of the individual winding pieces 5 protrude into these grooves. The sealing of the hydraulic connections of the winding pieces 5 is carried out by means of a seal 27, as shown for example in Fig. 7 is shown.

[0073] Fig. 7 shows a seal 27 with multiple passages, each designed to receive an end section 8 of a winding piece 5. The end sections 8 of the winding pieces 5 are each positively received in the passages 28, thereby ensuring the tightness of the arrangement. Alternatively or additionally, one or more seals (not shown) can also be provided on the seal 27.

[0074] The seal 27 and the hydraulic connection part 15 have opposing surfaces 29 and 30, respectively, which are complementary (in this case flat) and are pressed tightly against one another in the assembled state, thereby sealing the hydraulic connections of the individual winding pieces 5.

[0075] The seal 27 can, for example, be manufactured as a prefabricated component, e.g., from plastic. According to a preferred embodiment of the invention, the seal 27 comprises a potting compound that is poured into a space 48 in which the end sections 8 of the individual winding pieces 5 are located, and then spreads around the end sections 8. After some time, the potting compound hardens and forms the actual sealant, as shown in Fig. 7 The end sections 8 protrude slightly beyond the surface 29 of the seal 27. When the hydraulic connection part 15 is placed on the seal 27 in a subsequent step, the end sections 8 dip into the various connection openings 46 or channels 31, 32. Coolant can now be fed into the winding sections 5 via the front ends 33 of the individual winding sections 5, or coolant escaping from the winding sections 5 can be collected. All winding sections 5 are preferably hydraulically connected in parallel in the cooling circuit.

[0076] In the Fig. 1 In the illustrated embodiment of the electrical machine 1, the coolant flows into the electrical machine 1 via a coolant inlet 19 provided on the housing 13 of the electrical machine 1 and is fed from there via one or more channels to the hydraulic connection part 15. The coolant enters there from the outside via the passages 26 into the central coolant channel 32 and is then fed into the end sections 8 of the winding pieces 5 that are fluidly connected thereto, runs through the individual winding pieces 5 and exits again via the two channels 31. From there, the coolant is guided into a chamber 21 in which the distribution elements 11a - 11c are located. The coolant finally exits the electrical machine 1 again at the coolant outlet 20.

[0077] In the illustrated embodiment, the cross-section of the channels 31, 32 is selected such that the end sections 8 of the individual winding pieces 5 can penetrate into the channels 31, 32 without touching the hydraulic connection part 15. A free space thus remains between the end sections 8 of the winding pieces 5 and the walls of the channels 31, 32, whereby the end sections 8 are electrically insulated from the hydraulic connection part 15. Additional insulation elements can, but do not necessarily have to, be provided. Furthermore, this makes it possible to manufacture the hydraulic connection part 15 from an electrically conductive material, in particular metal.

[0078] Furthermore, power electronics of the electric machine 1 (not shown) can also be integrated into the cooling circuit and cooled by the coolant. By appropriately designing the coolant path through the electric machine 1, any desired component can, in principle, be cooled. A person skilled in the art will adapt the coolant path accordingly, based on their specialist knowledge.

[0079] Fig. 8 shows a sectional view of an electrical machine 1 according to a second embodiment of the invention, which is largely identical in construction to the electrical machine 1 of Fig. 1 . In contrast to the first embodiment, the contact rings 18a - 18b are not designed as solid metal rings, but consist of individual circuit boards 14a - 14d, which are designated here as a whole by the reference numeral 14.

[0080] The Fig. 9a - 9d show perspective views of the aforementioned circuit boards 14a-14d. Some of them are contacted by the previously described distribution elements 12a-12c and are thus each electrically connected to one of the electrical phases U, V, W or to an external phase terminal L1, L2, L3.

[0081] The individual circuit boards 14a - 14d preferably also comprise electrical conductor tracks (not shown) which electrically connect certain winding pieces 5 to one another and connect them in series to form the coils of the winding 4 of the electrical machine 1.

[0082] Each of the circuit boards 14a-14d further comprises a plurality of through-holes 36 for the end sections 8 of the winding pieces 5. Since the winding pieces 5 are inserted through all circuit boards 14a-14d, the number of through-holes 36 is the same in each case. The end sections 8 of the individual winding pieces 5 are soldered to one or more of the circuit boards 14a-14d, depending on the electrical wiring.

[0083] In the illustrated embodiment of the Fig. 9 und 10 The circuit board 14a is arranged opposite the hydraulic connection part 15. This is followed by the individual circuit boards 14b, 14c, and 14d. Alternatively, more than four circuit boards can be provided.

[0084] In the present case, the circuit board 14a is contacted by the connecting elements 12a, the circuit board 14b by the connecting elements 12b, and the circuit board 14c by the connecting elements 12c. The circuit board 14d is at zero potential. As shown in the Fig. 9b - 9d As can be seen, the individual circuit boards 14a - 14c each have several through-openings 43 through which the connecting elements 12a and / or 12b and / or 12c pass.

[0085] Due to its arrangement in the circuit board stack, the circuit board 14a has the most through-openings 43 and the circuit board 14c has the fewest through-openings 43 for connecting elements 12a - 12c.

[0086] Fig. 10Finally, FIG. 1 shows the entire contact arrangement in an assembled state. The individual circuit boards 14a - 14d are arranged in a circuit board stack 14 and are each electrically connected to one of the electrical distribution elements 11a - 11c via associated connecting elements 12a - 12c.

[0087] The outermost circuit board 14a is pressed against the hydraulic connection part 15 in the assembled state and thus simultaneously assumes the function of the previously described seal 27, which seals the hydraulic connections of one of the winding sections on the hydraulic connection part 15. Alternatively, another seal 27 can also be inserted or cast between the outermost circuit board 14a and the hydraulic connection part 15.

Claims

1. Electrical machine (1) with: - a rotor (3); - a stator (2); - several winding pieces (5) designed as hollow conductors, each of which is part of a cooling circuit of the electrical machine (1), - a hydraulic connection part (15) to which several of the winding pieces (5) are hydraulically connected, - a seal (27) having a plurality of passages (28) in each of which an end section (8) of one of the winding pieces (5) is arranged, - wherein the winding pieces (5) form different coils of a winding (4) of the electrical machine (1); - wherein a plurality of external phase terminals (L1 - L3) are provided which are electrically connected to the winding pieces (5); and - and wherein the hydraulic connection part (15) and the seal (27) have opposing surfaces (29, 30) which lie on one another in order to ensure a sealing of the individual connections of the winding pieces (5) on the hydraulic connection part (15); characterized in that - the hydraulic connection part (15) and the seal (27) are designed as annular components ; and - the hydraulic connection part (15) has at least one groove in its surface (30) opposite the seal (27), which groove is fluidically connected to several of the winding pieces (5), so that a coolant can be fed into the winding pieces (5) or a coolant emerging from the winding pieces (5) can be collected .

2. Electrical machine according to claim 1, characterized in that Fastening means (47) are provided to press the connecting part (15) and the seal (27) firmly against each other.

3. Electrical machine according to claim 1 or 2, characterized in that the seal (27) is made of an electrically insulating material.

4. Electrical machine according to one of the preceding claims, characterized in that the seal (27) is designed such that at least a first group of the end sections (8) is electrically insulated from a second group of the end sections (8).

5. Electrical machine according to one of the preceding claims, characterized in that the hydraulic connecting part (15) is designed such that the winding pieces (5) connected thereto are hydraulically connected in parallel.

6. Electrical machine according to one of the preceding claims, characterized in that the end sections (8) of the individual winding pieces (5) extend through the seal (27) and project in the direction of the hydraulic connection part (15) and there each dip into a connection opening (46) of the hydraulic connection part (15).

7. Electrical machine according to one of the preceding claims, characterized in that the passages (28) provided in the seal (27) are designed so that the end sections (8) of the winding pieces (5) are tightly received at their circumference.

8. Electrical machine according to claim 6, characterized in that the connection openings (46) provided in the hydraulic connection part (15) have a larger cross-section than the end sections (8) of the winding pieces (5) and that the end sections (8) are arranged such that they do not touch the hydraulic connection part (15).

9. Electrical machine according to one of the preceding claims, characterized in that the end sections (8) of the winding pieces (5) are glued in the seal (27).