Electric machine with multiple rigid winding elements in the form of hollow conductors

Abstract

The invention relates to an electric machine (1) having a rotor (3), a stator (2), a plurality of winding elements (5) in the form of hollow conductors, which form individual coils of a winding (4) of the electric machine (1) and are each part of a cooling circuit of the electric machine (1), and having a plurality of external phase terminals (L1-L3) electrically connected to the winding elements (5). According to the invention, a hydraulic connection portion (15) to which the winding elements (5) are hydraulically connected and a seal (27) having a plurality of through-openings (28) in which the ends (8) of the winding elements (5) are each arranged are provided, wherein the hydraulic connection portion (15) and the seal (27) have opposite surfaces (29, 30) which overlap one another in order to seal the individual connections of the winding elements (5) at the hydraulic connection portion (15).

Description

TECHNICAL FIELD

[0001] The invention relates to an electric machine having a rotor, a stator and a plurality of winding elements in the form of hollow conductors, which form individual coils of the electric machine winding and are each part of an electric machine cooling circuit. BACKGROUND

[0002] From the prior art, electric machines are known which have windings produced according to the so-called pin technology or hairpin technology. The pins or hairpins are usually rigid winding elements made of copper, which are inserted into the stator slots of the electric machine and generate a magnetic field when the electric machine is in operation. In the electric machines of the inner cooling type, the winding elements are designed as hollow conductors, which comprise a continuous channel through which a coolant is guided in order to cool the electric machine.

[0003] The rigid winding elements known from the prior art are mostly in the form of hairpins or rods. The known hairpins comprise, for example, two leg portions which extend substantially parallel and a curved transition region which connects the two leg portions. The known winding elements usually have an electrically insulating layer on their outer surface.

[0004] DE 195 02 308 A1 shows, for example, an electric machine having a rotor, a stator and a plurality of winding elements in the form of hollow conductors. In addition, a hydraulic connection portion having interfaces for the plurality of winding elements is provided, the hydraulic interfaces being in hydraulic communication with the end portions of the winding elements, and a seal having a plurality of through-holes is provided, in each of which an end portion of a respective winding element is arranged. However, the connection portion shown in DE 195 02 308 A1 only allows simultaneous hydraulic connection of all winding elements to a common coolant circuit. In addition, sealing the connection portion is relatively difficult. Other electric machines having inner cooling windings are known from WO 2018 / 033 307 A1 and DE 696 06 967 T2.

[0005] In such electric machines having hollow conductor windings formed from rigid winding elements, the hydraulic connection of the individual winding elements is in particular a technical challenge which still offers enough room for improvement. SUMMARY

[0006] It is therefore the task of the present invention to provide an electric machine having a hollow conductor winding composed of a plurality of rigid winding elements, which has a very simple structure, in particular with regard to the hydraulic connection of the individual winding elements.

[0007] According to the application, an electric machine is proposed, which comprises a rotor, a stator, a plurality of external phase connection terminals and a plurality of winding elements in the form of hollow conductors, which form the coils of the electric machine winding and are each part of the electric machine cooling circuit. The electric machine according to the application further comprises a hydraulic connection part, which has interfaces for the plurality of winding elements, to which the end sections of the winding elements are hydraulically connected, and a seal with a plurality of through-openings, in each of which an end section of a corresponding winding element is arranged, wherein the hydraulic connection part and the seal have surfaces directed towards each other, which abut against each other or are pressed against each other in order to ensure that the winding element interfaces on the hydraulic connection part are sealed.

[0008] The electric machine according to the application preferably comprises fastening means in order to firmly press the hydraulic connection part and the seal against each other. The fastening means can for example comprise one or more screws. The seal and the hydraulic connection part preferably each have a sealing surface directed in the axial direction of the electric machine. In this case, the two components are pressed against each other in the axial direction in order to seal the hydraulic connection of the winding elements.

[0009] The hydraulic connection part is preferably designed in the form of a ring as a hydraulic connection ring. Thereby, it can be arranged around the rotor, whereby the electric machine becomes very compact. The seal is preferably also a ring.

[0010] According to a preferred embodiment of the application, the hydraulic connection part is designed in such a way that the winding elements of the coils assigned to the different electrical phases (U, V, W) are electrically isolated from each other. Thus, the winding elements of the individual electrical phases can be connected to the hydraulic connection part.

[0011] The individual interfaces of the hydraulic connection part can be designed for accommodating a single winding element or for accommodating a plurality of winding elements.

[0012] According to a special embodiment of the application, the hydraulic connection part comprises at least one annular channel, which is fluidically connected to a plurality of winding elements, and through which the coolant can be fed into the individual winding elements or the coolant flowing out of the winding elements can be collected.

[0013] The at least one channel provided in the connection part is preferably designed as a circumferential annular groove. The groove is preferably open in the direction of the seal and is covered by the seal in the assembled state.

[0014] The hydraulic connection part is preferably designed in such a way that all winding elements are hydraulically connected in parallel.

[0015] The hydraulic connection part can for example be made of plastic, but can also be made of metal. In order to electrically isolate the connected winding elements with respect to the hydraulic connection part, for example electrically insulating elements can be provided.

[0016] According to a preferred embodiment of the application, the electrical separation is effected in such a way that the end portions of the rigid winding elements are arranged at a distance from the hydraulic connection portion, so that a gap remains between each winding element and the hydraulic connection portion. In this case, the additional spacer is not necessary, but it can still be provided.

[0017] The gap can be provided, for example, in that the connection openings provided in the hydraulic connection portion have a larger cross section than the end portions of the individual winding elements. The winding element end portions then project into the respective interface without contacting the hydraulic connection portion. Alternatively, the individual winding elements can also be arranged in such a way that they end at an axial distance from the hydraulic connection portion.

[0018] According to a preferred embodiment of the application, the seal is made of a filler material which is injected into the space provided with the winding element end portions in the assembled state of the electric machine, which then spreads around the end portions and hardens. In this case, the end portions of the individual winding elements preferably extend through the seal and project towards the hydraulic connection portion. The hydraulic connection portion can now be placed onto the end portions. In the assembled state, the opposite sides of the seal and the hydraulic connection portion lie closely against one another, so that the hydraulic connection of the winding elements at the hydraulic connection portion is ensured to be sealed.

[0019] The individual winding elements are preferably open at their end sides, so that coolant is fed in at one end and discharged at the other end.

[0020] In the electric machine according to the application, the end portions of the individual winding elements are preferably arranged in rows at different radii from one another. They preferably end at approximately the same axial height, i.e. in an axial plane. The electric machine can thus be assembled particularly easily.

[0021] The hydraulic connection according to the foregoing preferably comprises a plurality of annular channels for distributing or collecting coolant to or from the individual winding elements. At least one of the channels is preferably designed to be in fluid communication with the end portions of at least two rows of winding elements.

[0022] The end portions of the individual winding elements are preferably arranged to extend through the seal, wherein they project towards the hydraulic connection portion and are inserted into the respective connection openings of the hydraulic connection. The interface or the connection openings can be designed to accommodate the end portions of the winding elements alone or in multiples.

[0023] Furthermore, the access opening provided in the seal is preferably designed to accommodate the end portions of the winding elements therein.

[0024] The end portions of the winding elements can also be bonded in the seal or the hydraulic connection portion.

[0025] The application also relates to a method for hydraulically connecting a plurality of rigid winding elements in the form of hollow conductors of an electrical machine to a hydraulic connection having a plurality of interfaces for the winding element ends, wherein the method comprises the following steps: positioning the ends in a space, casting the space with a casting compound which flows around the winding element ends and hardens after a certain period of time to form a seal, wherein the amount of casting compound is so dimensioned that the ends protrude from the seal, and then placing the hydraulic connection on the seal such that the protruding ends are inserted into the connection openings of the hydraulic connection and the opposing surfaces of the hydraulic connection and the seal are pressed against one another to seal the hydraulic connection of the winding elements.

[0026] It is possible to insert a further seal between the hydraulic connection and the seal.

[0027] Preferably, the electrical machine according to the application also comprises a plurality of contact rings which are designed to electrically connect the plurality of winding elements to one of the corresponding external phase terminals. By means of the contact rings described above, the relevant terminals of the coils or winding elements can be easily contacted and connected to the respective external phase terminal to which they belong. This is advantageous, in particular, in electrical machines whose phases (U, V, W) have a plurality of parallel coils, i.e. in which each electrical phase or each external phase terminal is assigned a plurality of parallel coils.

[0028] According to a preferred embodiment of the application, the contact rings comprise a plurality of terminals for electrically contacting the winding elements, wherein the terminals are preferably distributed uniformly in the circumferential direction of the contact rings.

[0029] According to a preferred embodiment of the application, the electrical machine also comprises a plurality of power distribution elements, wherein each power distribution element is electrically connected to one of the external phase terminals to which it belongs.

[0030] Each power distribution element is preferably electrically connected to one of the aforementioned contact rings by means of a plurality of electrical connection elements. In this case, the electrical machine comprises a plurality of power distribution elements which each distribute the current flowing through the external phase terminals to a plurality of electrical connection elements, the electrical connection elements electrically connecting the power distribution elements and the contact rings, and the contact rings each contacting a defined number of parallel coils. In this case, the current path starting from the external phase terminals (L1, L2, L3) leads via the respective power distribution element, a plurality of electrical connection elements and one of the contact rings to the coils of the winding, and further to a reference potential (e.g. zero or another phase).

[0031] The electrical connection elements can be designed, for example, as rod-shaped elements. The connection elements preferably extend substantially in the axial direction of the electrical machine. Furthermore, they are preferably distributed uniformly in the circumferential direction of the electrical machine.

[0032] The power distribution elements preferably have mutually different diameters, thereby simplifying the electrical circuit layout. The power distribution elements are preferably designed in the form of rings.

[0033] The contact elements and / or the power distribution elements are preferably arranged side by side in the axial direction of the electric machine.

[0034] According to the application, the winding elements in the form of hollow conductors can for example be in the form of rods. According to a further embodiment of the application, the winding elements are in the form of hairpins, in which case the winding elements comprise two leg portions and a curved transition region connecting the two leg portions. The two leg portions are arranged substantially parallel and preferably each have a profile which corresponds to the cross section of the associated stator slot. In principle, the dimensions of the winding elements according to the application can be set such that they individually occupy a slot or together with one or more further winding elements occupy a slot.

[0035] The winding elements according to the application are preferably made of copper, aluminium or an alloy of one of the aforementioned materials. On their outer surfaces, they preferably have an electrically insulating layer.

[0036] The individual coils of the winding are preferably formed by a plurality of rigid winding elements which are electrically connected in series.

[0037] The aforementioned power distribution elements, contact rings and electrical connection elements arranged between the power distribution elements and the contact rings can be capable of transporting very high current densities. In order to improve the cooling of the components, a special embodiment of the application provides that, in addition to the winding, the power distribution elements and / or the contact rings and / or the connection elements are designed as hollow conductors, so that a coolant can be conducted through the components. The power distribution elements, contact rings and / or connection elements thus form part of the cooling circuit of the electric machine themselves, so that they can be cooled particularly effectively.

[0038] As an alternative to the aforementioned internal cooling, the components can also be cooled from the outside. For example, the components can be arranged in one or more cavities through which a coolant flows.

[0039] In principle, every component which is subjected to high thermal loads can be cooled by suitable arrangement or design of the coolant paths. In the case of a hollow conductor-like structure, the individual components can be cooled from the inside. Alternatively, a coolant can also flow through on the outside in order to cool the associated components. The cooling method depends on the technical requirements and can be easily implemented by the person skilled in the art by taking a practical approach.

[0040] According to a preferred embodiment of the application, the contact rings each have a plurality of arms, at each of which at least one winding element is electrically contacted.

[0041] The contact ring described in the introduction can be made of solid metal as described. According to another embodiment of the application, the contact ring is made of printed circuit board material, which contains printed conductors that electrically contact the individual winding elements.

[0042] Furthermore, a common or possibly different circuit board can be designed for electrically connecting a plurality of winding elements in series to form a coil of the electrical winding.

[0043] The electrical machine according to the application can also have at least one contact plate having a plurality of through-holes through which the individual winding elements pass, wherein the contact plate also comprises electrical connections by means of which certain winding elements are electrically connected in series in order to form a coil of the electrical winding.

[0044] The electrical and hydraulic connections of the individual winding elements are preferably made on only one side of the electrical machine. In the case of rod-shaped winding elements, however, the electrical and / or hydraulic connections of the individual winding elements can also be made on both sides of the electrical machine.

[0045] According to a preferred embodiment of the application, the ends of the individual winding elements are preferably arranged in rows, in particular in a ring. The ends are preferably arranged parallel to one another and preferably all point in the axial direction of the electrical machine. The ends preferably end at approximately the same axial height, i.e. approximately in the same plane. This will significantly simplify the electrical and hydraulic connections of the winding elements.

[0046] The contact ring and / or the distribution element are preferably designed in the form of a disc. BRIEF DESCRIPTION OF DRAWINGS

[0047] The application will be described in more detail below by way of example with reference to the drawings, in which:

[0048] Figure 1 A cross-sectional view of an electrical machine according to a first embodiment of the application having a solid metal contact ring is shown;

[0049] Figure 2 A perspective view of an electrical machine winding element in the form of a hairpin is shown;

[0050] Figure 3a and 3b Various views of an arrangement comprising a plurality of distribution elements for distributing the electrical current input at external phase terminals are shown;

[0051] Figures 4a-4c A contact ring of an electrical machine according to the application is shown;

[0052] Figure 5 A contact ring structure of the contact ring of Figures 4a-4c is shown;

[0053] Figure 6a and 6bdifferent views of a hydraulic connection according to a first embodiment of the application are shown;

[0054] Figure 7 a cross-sectional view of a hydraulic connection and a seal according to a special embodiment of the application is shown;

[0055] Figure 8 a cross-sectional view of an electric machine with an electric contact ring in the form of a printed circuit board according to a second embodiment of the application is shown;

[0056] Figures 9a-9d different printed circuit boards of an electric machine, which are used as contact rings for electrically contacting certain winding parts of the electric machine winding;

[0057] Figure 10 a perspective view of an electric contact mechanism is shown, which comprises Figure 3a and 3b a power distribution element as well as a printed circuit board as shown in Figures 9a-9d . DETAILED DESCRIPTION

[0058] Figure 1 A cross-sectional view of an electric machine 1 with a stator 2, a rotor 3 and a winding 4 formed by a plurality of rigid winding parts 5 is shown. The rigid winding parts 5 are designed as hollow conductors here and comprise a continuous channel 9 through which a coolant is guided in order to cool the electric machine 1. The winding parts 5 are hydraulically connected in parallel here and are each part of a cooling circuit of the electric machine 1.

[0059] In the embodiment shown in Figure 1 , the winding parts 5 are each arranged individually in a slot 24 of the stator 2 of the electric machine 1. The cross section of the winding parts 5 is matched to the cross section of the slots 24 here, so that they are essentially gaplessly received in the slots 24. Alternatively, however, more than one winding part 5 can also be provided in each slot 24.

[0060] As a coolant, for example, oil, heat-conducting oil, heat-conducting liquid or carbon dioxide can be used.

[0061] The electric machine 1 also comprises a housing 13 with a housing cover 17, in which all components of the electric connection and the hydraulic connection are accommodated.

[0062] Furthermore, a fastening element 47 is provided, which is designed as a screw here, by means of which the housing is tightened. The electric machine is designed here in such a way that, by tightening the fastening element, the hydraulic connection 15 is also simultaneously pressed against the seal 27. The structure and function of the mentioned components will also be explained in detail below.

[0063] In the electric machine 1 shown in Figure 1 , the winding parts 5 are designed as so-called hairpins, as is exemplarily shown in Figure 2 . Figure 2The shown winding element 5 comprises two legs 6 which extend substantially parallel and a curved transition region 10 which connects the two legs 6 to each other. The shown hairpin is designed as a hollow conductor and comprises a continuous channel 9 which leads from one end 8 to the other end 8 and through which a coolant is guided in order to cool the winding 4 of the electric machine 1 in operation. The hairpin is open at its end-side tips 33, respectively. Thus, one of the end-side tips 33 can be used as coolant inlet and the other end-side tip 33 can be used as coolant outlet.

[0064] Figure 2 The shown winding element 5 can be made of copper, for example. Preferably, an electrically insulating layer is provided on its outer surface.

[0065] The winding element 5 can have a circular or angular profile, for example. The winding element 5 can also have a profile which differs from each other in different sections. According to a preferred embodiment, the profile is circular at the ends.

[0066] Figure 1 The shown electric machine 1 is designed as a three-phase machine and accordingly has three external phase terminals L1, L2 and L3 to which the electrical phases U, V and W are applied. The winding 4 of the electric machine 1 is designed here such that it comprises for each electrical phase U, V and W a plurality of parallel connected coils. The individual winding elements 5 are accordingly electrically connected such that a plurality of winding elements form a coil in series, respectively, and a plurality of such coils belonging to the same electrical phase U, V, W are connected in parallel. According to a specific embodiment of the present application, each phase U, V, W can comprise eight parallel connected coils, for example. The winding 4 of the electric machine can of course also have more or less parallel connected coils.

[0067] The ends 8 of the winding elements 5 which are at the phase potential U, V, W are connected to the respective assigned external phase terminal L1, L2 or L3 by an electrical contact mechanism which will be described in more detail below.

[0068] In this embodiment, the electrical contact mechanism comprises a set of three power distribution elements 1 1 a, 1 1 b, 1 1 c as shown, for example, in Figure 3a and 3b Each power distribution element 1 1 a, 1 1 b, 1 1 c is electrically connected to one of the corresponding external phase terminals L1, L2, L3. In the shown embodiment, the power distribution element 1 1 a is electrically connected to the phase terminal L1, the power distribution element 1 1 b is electrically connected to the phase terminal L2 and the power distribution element 1 1 c is electrically connected to the phase terminal L3. The three power distribution elements 1 1 a- 1 1 c are arranged side by side in the axial direction B of the electric machine 1 and are electrically isolated from each other.

[0069] Each power distribution element 11a, 11b, 11c further comprises a plurality of receptacles 45 for the electrical connection elements 12a-12d, which are preferably uniformly distributed in the circumferential direction of the power distribution element. The individual power distribution elements 11a, 11b, 11c are essentially used to distribute the current supplied at the phase connection L1, L2, L3 in the circumferential direction of the electric machine 1 and to conduct it to the subsequent contact rings 18a-18d. Each of the power distribution elements 11a-11d is electrically connected to the respective contact ring 18a-18d by means of the plurality of electrical connection elements 12a-12d.

[0070] Figures 4a-4c The individual contact rings 18a-18c according to one embodiment of the application are shown. Here, the contact ring 18a is electrically connected to the associated power distribution element 11a and the phase connection L1, the contact ring 18b is electrically connected to the associated power distribution element 11b and the phase connection L2, and the contact ring 18c is electrically connected to the associated power distribution element 11c and the phase connection L3.

[0071] As can be seen in Figures 4a-4c , the electrical connection elements 12a-12c are each fixed on the associated contact ring 18a-18c and are uniformly distributed in the circumferential direction of the contact ring 18a-18c. In the assembled state, the contact rings 18a-18c are essentially transverse to the axial direction B of the electric machine 1, and the electrical connection elements 12a-12c extend essentially in the axial direction B.

[0072] Each electrical contact ring 18a-18c comprises a plurality of arms 23 for electrically contacting the end portions 8 of the winding elements 5 of a certain electrical phase U, V or W. In the present embodiment, each contact ring 18a-18c comprises eight arms 23 for electrically contacting one of the eight winding elements 5 of one of the eight parallel coils, respectively. The arms 23 have different lengths from one another in order to contact the radially more inner or outer end portions 8 of the winding elements 5. Each arm 23 comprises a contact opening 16 via which the end portion 8 of a winding element 5 is inserted and soldered.

[0073] In the electric machine 1 according to the application, the end portions 8 of the winding elements 5 are preferably arranged in rows, in particular in a ring. The end portions 8 of the winding elements 5 are preferably arranged parallel to one another side by side and preferably all point in the axial direction B. The end portions 8 preferably all end at the same axial height, i.e. approximately in the same plane. This simplifies the electrical contacting of the individual winding elements 5 and their hydraulic connection to the cooling circuit.

[0074] Figure 5 The contact rings 18a-18c of the electric machine 1 in the assembled state are shown. As can be seen, the contact rings 18a-18c are arranged side by side in the axial direction B of the electric machine 1 and are at the same time electrically isolated from one another. Figures 4a-4c

[0075] ​In addition to the electrical connection of the individual winding elements 5 to the respective external phase connection L1, L2, L3, it is also necessary to connect certain winding elements 5 to one another in series to form the coils of the winding 4 of the electric machine 1. For the series connection, for example, simple electrical conductors can be used which are soldered between the desired winding elements.

[0076] According to a preferred embodiment of the application, however, an electrical contact plate with electrical connections is provided. Before the electrical contact plate is discussed, the hydraulic connection of the individual winding elements 5 will first be described:

[0077] Figure 6a and 6b Different perspective views of the hydraulic connection portion 15 are shown, to which all winding elements 5 are hydraulically connected. The hydraulic connection portion 15 comprises a plurality of interfaces or connection openings 46, which are designed here as annular channels 31 and 32, which are in fluid communication with a plurality of winding elements 5, respectively, and through which the coolant is fed into the winding elements 5 or collected from the winding elements 5.

[0078] The middle channel 32 of the hydraulic connection portion 15 is designed here to be wider than the other two channels 31 and to span two adjacently arranged end portions 8 rings. One of the other two channels 31 is arranged radially outside the middle channel 32 and the other radially inside the middle channel, said other two channels being assigned to the respective unique end portion 8 ring. All channels 31, 32 extend essentially over the entire circumference of the hydraulic connection portion 15.

[0079] In the present case, the coolant is fed via the middle channel 32 into the winding elements 5 connected thereto and flows out at the other end of the winding elements 5 into the outer or inner channel 31. In the region of the middle channel 32, a plurality of through openings 26 are provided, through which the coolant enters the channel 32. In addition, in the region of the outer channel 31, a plurality of through openings 44 are provided, through which the coolant flows out of the hydraulic connection portion 15. Further inlets or outlets can also be provided on the peripheral surface of the hydraulic connection portion 15.

[0080] The hydraulic connection portion 15 also comprises a plurality of through openings 25, through which the connecting elements 12a-12c between the contact rings 18a-18c and the power distribution elements 11a-11c pass.

[0081] As can be seen in Figure 6a and 6b , the channels 31, 32 are designed as annular grooves, which are arranged in the surface of the hydraulic connection portion 15 that is directed toward the contact rings 18a-18d. In the first embodiment of the electric machine 1 according to Figure 1 , the end portions 8 of the individual winding elements 5 protrude into the respective groove. The sealing of the hydraulic connection of the winding elements 5 is achieved here by means of a seal 27, as can be seen inFigure 7 The example shown in Fig. 1 is a motor 1 having a stator 2 and a rotor 3. The stator 2 is formed by a plurality of winding assemblies 5, which are arranged in a circular pattern around the rotor 3. The winding assemblies 5 are electrically connected to one another and to the rotor 3 by means of a plurality of electrical connections 6, 7. The rotor 3 is formed by a plurality of rotor segments 4, which are arranged in a circular pattern around the stator 2. The rotor segments 4 are electrically connected to one another and to the stator 2 by means of a plurality of electrical connections 6, 7.

[0082] Figure 7 The seal 27 is shown having a plurality of communication openings, which are designed to accommodate the end portions 8 of the respective winding assemblies 5. The end portions 8 of the winding assemblies 5 are accommodated in the communication openings 28 in a form-fitting manner, thereby ensuring the sealing of the structure. Alternatively or additionally, one or more seals (not shown) can be provided at the seal 27.

[0083] The seal 27 and the hydraulic connection portion 15 have opposing surfaces 29 and 30, which are designed to be shape-complementary (in the present case flat) and to be firmly pressed against one another in the assembled state, thereby sealing the hydraulic connection of the individual winding assemblies 5.

[0084] The seal 27 can be manufactured, for example, in the form of a preform, for example, of plastic. According to a preferred embodiment of the application, the seal 27 comprises a filler, which is cast into the space 48, in which the end portions 8 of the individual winding assemblies 5 are located, and then spreads around the end portions 8. After a certain period of time, the filler hardens and forms a true seal, as shown in Fig. 2. The end portions 8 protrude here beyond the surface 29 of the seal 27 by a certain distance. If the hydraulic connection portion 15 is now placed on the seal 27 in the next working step, the end portions 8 are inserted into the respective different connection openings 46 or channels 31, 32. The coolant can now be fed into the winding assemblies 5 or collected from the winding assemblies 5 via the end-side ends 33 of the respective winding assemblies 5. All winding assemblies 5 are preferably hydraulically connected in parallel in the cooling circuit. Figure 7

[0085] In the embodiment of the motor 1 shown in Fig. 1, the coolant flows into the motor 1 via the coolant inlet 19 provided on the housing 13 of the motor 1 and from there via one or more channels to the hydraulic connection portion 15. The coolant enters the central coolant channel 32 from the outside through the communication openings 26 there and is fed into the end portions 8 of the winding assemblies 5, which are in fluid communication therewith, flows through the individual winding assemblies 5 and flows out again at the two channels 31. From there, the coolant is fed into the cavities 21, in which the electrical distribution elements 11a-11c are located. The coolant finally flows out of the motor 1 again at the coolant outlet 20. Figure 1

[0086] In the embodiment shown, the cross-section of the channels 31, 32 is chosen such that the end portions 8 of the individual winding assemblies 5 can be inserted into the channels 31, 32 without contacting the hydraulic connection portion 15. Thus, a clearance is left between the end portions 8 of the winding assemblies 5 and the walls of the channels 31, 32, whereby the end portions 8 are electrically isolated with respect to the hydraulic connection portion 15. Thus, an additional insulation can be provided, but is not necessary. Furthermore, the hydraulic connection portion 15 can thus also be made of an electrically conductive material, in particular metal.​​

[0087] Furthermore, the power electronics (not shown) of the electric machine 1 can also be connected into the cooling circuit and cooled by the coolant. By corresponding design of the coolant path through the electric machine 1, it is possible in principle to cool any component as required. The person skilled in the art will adapt the coolant path accordingly within his expert knowledge depending on the requirements.

[0088] Figure 8 A cross-sectional view of an electric machine 1 according to a second embodiment of the application is shown, which is largely constructed identically to the electric machine 1 according to the first embodiment. Figure 1 The difference to the first embodiment is that the contact rings 18a-18b are not designed as solid metal rings, but rather consist of individual printed circuit boards 14a-14d, which are designated by the reference numeral 14 in general here.

[0089] Figures 9a-9d A perspective view of the printed circuit boards 14a-14d is shown. Some of the printed circuit boards are contacted by the aforementioned connection elements 12a-12c and are thus electrically connected to one of the electrical phases U, V, W or one of the external connection terminals L1, L2, L3, respectively. The printed circuit boards 14a-14d preferably also comprise printed electrical conductors (not shown), which electrically connect and series-connect the individual winding elements 5 to one another to form the coils of the winding 4 of the electric machine 1.

[0090] Each of the printed circuit boards 14a-14d also comprises a plurality of through-holes 36 for the end portions 8 of the winding elements 5. Since the winding elements 5 pass through all of the printed circuit boards 14a-14d, the number of through-holes 36 is always equal. The end portions 8 of the individual winding elements 5 are soldered to one or more of the printed circuit boards 14a-14d, respectively, depending on the electrical connection.

[0091] In the embodiment shown in Figures 9 and Figure 10 The printed circuit board 14a is opposite the hydraulic connection portion 15. Next are the printed circuit boards 14b, 14c and 14d. It is alternatively possible to provide more than four printed circuit boards.

[0092] In the present case, the printed circuit board 14a is contacted by the connection element 12a, the printed circuit board 14b is contacted by the connection element 12b, and the printed circuit board 14c is contacted by the connection element 12c. The printed circuit board 14d is at zero potential. As can be seen in Figures 9b-9d These printed circuit boards 14a-14c each have a plurality of through-holes 43, through which the connection elements 12a and / or 12b and / or 12c extend. Since they are arranged in a printed circuit board stack, the printed circuit board 14a has the most through-holes 43 for the connection elements 12a-12c, and the printed circuit board 14c has the fewest through-holes 43.

[0093] Finally,Figure 10 The entire contact mechanism in the assembled state is shown. The printed circuit boards 14a-14d are at this time arranged in the form of a printed circuit board stack 14 and are electrically connected to one of the corresponding power distribution elements 11a-11c by the associated connecting elements 12a-12c.

[0094] In the assembled state, the outermost printed circuit board 14a is pressed against the hydraulic connection part 15 and thus simultaneously assumes the function of the above-mentioned seal 27, which seals the hydraulic connection of one of the winding assemblies to the hydraulic connection part 15. Alternatively, a further seal 27 can also be inserted or cast between the outermost printed circuit board 14a and the hydraulic connection part 15.

Claims

1. An electric machine (1) having: - a rotor (3); - a stator (2); - a plurality of winding elements (5) in the form of hollow conductors, which form respectively a part of a cooling circuit of the electric machine (1); - a hydraulic junction (15) to which the winding elements (5) are hydraulically connected; and - a seal (27) which is arranged between the junction (15) and the winding elements (5); characterized in that: - the junction (15) and the seal (27) have surfaces (29, 30) which face each other and which abut against each other to ensure the sealing of the respective connection of the winding elements (5) to the junction (15); wherein the facing surfaces (29, 30) are oriented in an axial direction with respect to the electric machine (1); - the junction (15) has, in a surface (30) thereof which is opposite the seal (27), an inlet annular groove and two outlet annular grooves, the inlet annular groove being located in the middle, one of the outlet annular grooves being arranged radially outside the inlet annular groove and the other outlet annular groove being arranged radially inside the inlet annular groove, the inlet annular groove and the two outlet annular grooves being in fluid communication with the winding elements (5) so that coolant can enter the inlet annular groove from the outside and be fed to the winding elements (5), after which the coolant flows through the winding elements (5) and exits from the outlet annular grooves. Fastening means (47) are provided for firmly pressing the junction (15) and the seal (27) against each other. The seal (27) is made of electrically insulating material. The junction (15) is designed so that the winding elements (5) connected thereto are hydraulically connected in parallel to each other. The ends (8) of the winding elements (5) protrude through the seal (27) and towards the junction (15) and are inserted therein in respective connection openings (46) of the junction (15). - a seal (27) defining a plurality of through openings (28) configured to house the end portions (8) of the respective winding assemblies (5), wherein, An access opening (28) provided in the seal (27) is designed so that the ends (8) of the winding elements (5) are sealingly received therearound. The connection openings (46) provided in the junction (15) have a cross section which is larger than the ends (8) of the winding elements (5) and the ends (8) are arranged so as not to touch the junction (15). The ends (8) of the winding elements (5) are glued in the seal (27). ​ 2. The electric machine of claim 1, wherein, ​ 3. The electric machine of claim 1 or 2, characterized in that ​ 4. The electric machine of claim 1, wherein, ​ 5. The electric machine of claim 1, wherein, ​ 6. The electric machine of claim 1, wherein, ​ 7. The electric machine of claim 1, wherein, ​ 8. The electric machine of claim 1, wherein, ​

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