Stator, electrical machine and electrical drivetrain

Abstract

The invention relates to a stator (1) for an electrical machine (2), in particular for an electrical machine (2) within a drivetrain (3) of a motor vehicle (4), the stator comprising a stator body (5) having a multiplicity of stator teeth (6) arranged in circumferentially distributed fashion and stator slots (7) formed between the stator teeth (6) and extending through the stator body (5) in the axial direction, wherein electrical conductors (8) of a stator winding (9) are arranged in the stator slots (7) and emerge from an end face of the stator body (5) and at least form a winding head (10), wherein a cooling fluid (11) can be applied to the winding head (10) during operation of the electrical machine (2) and flows through the stator slots (7), and the stator body (5) has an upper half (12) and a lower half (13) when viewed in the direction of gravity, and a fluid-conducting ring (15) is located on the cylindrical ring-type winding head (10).

Description

[0001] Stator, electric machine and electric drive train

[0002] The present invention relates to a stator for an electrical machine, in particular for an electrical machine within a drive train of a motor vehicle, comprising a stator body with a plurality of circumferentially distributed stator teeth and stator slots formed between the stator teeth and extending in the axial direction through the stator body, wherein electrical conductors of a stator winding are arranged in the stator slots and emerge from the front side of the stator body at least to form a winding head, wherein the winding head can be acted upon by a cooling fluid flowing through the stator slots during operation of the electrical machine, and the stator body has an upper half and a lower half viewed in the direction of gravity. The invention further relates to an electrical machine and an electrical drive train.

[0003] Electric motors are increasingly being used to power motor vehicles, creating alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and also to provide users with the same level of driving comfort they are accustomed to.

[0004] A detailed description of an electric drive can be found in an article in the magazine ATZ 113th year, 05 / 2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrated and flexible electric drive unit for electric vehicles. This article describes a drive unit for one axle of a vehicle which comprises an electric motor which is arranged concentrically and coaxially to a bevel gear differential, with a switchable 2-speed planetary gear set arranged in the power train between the electric motor and bevel gear differential, which is also positioned coaxially to the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and, thanks to the switchable 2-speed planetary gear set, allows a good compromise between climbing ability, acceleration and energy consumption.Such drive units are also referred to as e-axles or electrically operated drive trains.

[0005] In addition to purely electric drivetrains, hybrid drivetrains are also known. Such drivetrains in hybrid vehicles typically comprise a combination of an internal combustion engine and an electric motor, enabling purely electric operation—for example, in urban areas—while maintaining sufficient range and availability, especially for long-distance journeys. Furthermore, in certain operating situations, it is possible to use both the internal combustion engine and the electric motor simultaneously.

[0006] In the development of electric motors intended for electric axles or hybrid modules, there is a continuing need to increase their power densities, making the necessary cooling of the electric motors increasingly important. Due to the necessary cooling performance, hydraulic fluids, such as cooling oils, have become the preferred solution in most concepts for dissipating heat from the thermally stressed areas of an electric motor.

[0007] Jacket cooling and winding head cooling, for example, are known from the state of the art for cooling electrical machines using hydraulic fluids. While jacket cooling transfers the heat generated at the outer surface of the stator core into a cooling circuit, with winding head cooling, the heat is transferred directly to the fluid at the conductors outside the stator core in the area of ​​the winding heads.

[0008] Further improvements are offered by separately designed cooling channels, which are introduced both into the laminated core of the stator (see e.g. EP3157138 A1) and into the slot in addition to the conductors (see e.g. Markus Schiefer: Indirect winding cooling of highly utilized permanent magnet synchronous machines with tooth-wound coil winding, dissertation, Karlsruhe Institute of Technology (KIT), 2017). Concepts are also known in which hydraulic fluid flows directly around the windings in order to increase the power density. Improved cooling with direct contact between hydraulic fluid and conductor in the slot is already known in principle from the prior art. For example, DE102015013018 A1 describes a solution for electrical machines with single-tooth windings, in which the fluid flows directly around the windings wound around the teeth.

[0009] In this context, so-called direct slot cooling and winding head cooling systems have become known. These systems, using a liquid cooling medium directly flowing around the slots, can achieve very effective cooling of the electrical conductors and, by applying the cooling medium to the winding heads, can achieve good heat dissipation from the winding heads. In this case, it is usually necessary to enclose the corresponding winding heads to guide the cooling medium.

[0010] In stators with direct slot cooling and a non-encapsulated winding head, uniform cooling of the winding head is not automatically guaranteed. Unlike closed / encapsulated winding heads, the cooling fluid can drip off due to gravity and the lack of channeling before reaching all surfaces of the winding head that need to be cooled. However, open cooling can be advantageous because it eliminates the technically complex sealing of the entire winding head, thus reducing costs compared to a fully encapsulated machine.

[0011] The object of the invention is to provide a stator that has a high power density, a high degree of system integration, and is easy to install. Furthermore, the object of the invention is to realize an improved electric machine and an optimized drive train for a motor vehicle.

[0012] This object is achieved by a stator for an electrical machine, in particular for an electrical machine within a drive train of a motor vehicle, comprising a stator body with a plurality of circumferentially distributed stator teeth and stator slots formed between the stator teeth and extending in the axial direction through the stator body, wherein electrical conductors of a stator winding are arranged in the stator slots and emerge from the front side of the stator body at least to form a winding head, wherein the winding head can be acted upon by a cooling fluid flowing through the stator slots during operation of the electrical machine, and the stator body has an upper half and a lower half viewed in the direction of gravity, wherein a fluid guide ring is positioned on the cylindrical ring-like winding head, which fluid guide ring has a first cylindrical ring-like fluid guide section,whose outer diameter is smaller than the inner diameter of the winding head and which has an axial overlap with the winding head and which further extends in the circumferential direction of the fluid guide ring at least through the upper half of the stator body, wherein the fluid guide ring further comprises a second cylinder ring-section-like fluid guide section, whose inner diameter is larger than the outer diameter of the winding head and which has an axial overlap with the winding head and which further extends in the circumferential direction of the fluid guide ring at least partially through the lower half of the stator body and has a first fluid passage opening from which cooling fluid can flow out under the influence of gravity.

[0013] This has the advantage that a completely encapsulated winding head is not required and yet good cooling fluid guidance and wetting via the winding head can be ensured.

[0014] The fluid guide ring can be made of a plastic. In principle, it would also be possible for the fluid guide ring to be formed from a metallic material without cutting, for example, from sheet metal using a forming process.

[0015] A thermosetting plastic, such as an epoxy resin, could be used as the plastic for molding the plastic injection-molded element, but other plastics are also conceivable in principle. It is also conceivable for the fluid guide ring to be formed from several different plastics, for example, using a dual-injection molding process. The fluid guide ring is preferably formed in one piece. However, it is also conceivable for the fluid guide ring to be formed from multiple parts, in which case it is further preferred for the multiple parts of the fluid guide ring to be molded from the same plastic.

[0016] This provides the advantage of providing direct fluidic cooling of a thermally highly stressed area of ​​the stator, namely the winding head. The fluid guide ring provided for this purpose can be attached to the stator body in a particularly simple and easy-to-install manner. For this purpose, the cooling fluid present in a fluid-cooled stator is directed into the winding head area, allowing it to be directly exposed to the cooling fluid. This enables highly efficient cooling of the thermally highly stressed winding head areas, which can contribute to achieving high power density and reduced losses in the electrical machine.

[0017] The stator according to the invention is preferably designed for use in a radial flux machine. A stator for a radial flux machine is typically cylindrical and generally consists of electrically insulated, layered, and stacked laminations. Distributed around the circumference, grooves are recessed into the electrical lamination, extending essentially parallel to the rotor shaft. These grooves accommodate the stator winding or parts of the stator winding. The stator grooves preferably have a substantially U-shaped cross-sectional contour. Most preferably, the stator grooves have straight groove walls extending in the radial direction.

[0018] Particularly preferably, a winding with conductors can be embedded in the stator slots of the stator according to the invention. A conductor is in particular an electrically conductive conductor with two parallel conductor sections whose lengths are significantly greater than their diameters. The conductor sections can in principle have any cross-sectional shape other than a circular shape. Rectangular cross-sectional shapes are preferred, as these allow high packing and consequently power densities to be achieved. Most preferably, a conductor is made of copper. Preferably, a conductor has insulation. To insulate the conductors, for example, mica paper, which for mechanical reasons can be reinforced by a glass fabric carrier, can be wound in strip form around one or more windings impregnated with a hardening resin.In principle, it is also possible to use a curable lacquer layer without mica paper to insulate a conductor.

[0019] Most preferably, the winding is designed as a hairpin winding or wave winding. In this context, it is further preferred that the conductors are designed as hairpin conductors.

[0020] The stator according to the invention preferably further comprises a stator body. The stator body can be formed in one piece or in multiple pieces, in particular segmented. A one-piece stator body is characterized in that the entire stator body is formed in one piece over its circumference. The stator body is generally formed from a plurality of stacked laminated electrical sheets, each of the electrical sheets being formed to form a closed circular ring. A segmented stator body is characterized in that it is constructed from individual stator segment parts. The stator body can be constructed from individual stator teeth or stator tooth groups, each individual stator tooth or each individual stator tooth group being formed from a plurality of stacked laminated electrical sheets, each of the electrical sheets being designed as a stator segment sheet part.

[0021] The stator body is preferably formed from one or more stator lamination stacks. A stator lamination stack is understood to be a plurality of laminated individual laminations or stator laminations, usually made of electrical steel, which are stacked and stacked together to form a so-called stator lamination stack. The individual laminations can then be held together in the lamination stack, for example, by gluing, welding, or screwing.

[0022] The stator teeth of the stator are preferably formed in the stator body. Stator teeth are components of the stator body that are circumferentially spaced, tooth-like, radially inwardly directed parts of the stator body, with an air gap for the magnetic field formed between their free ends and a rotor body. The air gap is the gap existing between the rotor and the stator. In a radial flux machine, this is a substantially circular gap with a radial width that corresponds to the distance between the rotor body and the stator body.

[0023] The stator is particularly intended for use in an electric machine within a drive train of a motor vehicle. The electric machine is particularly intended for use within a drive train of a hybrid or fully electric motor vehicle. In particular, the electric machine is dimensioned such that vehicle speeds of greater than 50 km / h, preferably greater than 80 km / h and in particular greater than 100 km / h can be achieved. The electric machine particularly preferably has an output of greater than 30 kW, preferably greater than 50 kW and in particular greater than 70 kW. It is further preferred that the electric machine provides rotational speeds of greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, very particularly preferably greater than 12,500 rpm.

[0024] According to an advantageous embodiment of the invention, it can be provided that the majority, preferably all, of the electrical conductors have a substantially rectangular cross-section. The advantage of this embodiment is that generally standard electrical conductors can be used to form the stator winding, which is particularly advantageous in terms of stator manufacturing costs.

[0025] The cooling fluid in the stator according to the invention has the function of dissipating heat as efficiently as possible from heating areas of the stator and preventing undesirable overheating of these areas. In addition to this main task, the cooling fluid can also provide lubrication and corrosion protection for moving parts and the metal surfaces of the cooling system of the electric machine. Furthermore, it can also, in particular, dissipate contaminants (e.g., from abrasion), water, and air. The cooling fluid is preferably a liquid. The cooling fluid can, in particular, be an oil. In principle, however, it is also conceivable to use aqueous cooling fluids, for example, emulsions such as water-glycol mixtures.

[0026] The stator's cooling fluid can be connected to a hydraulic cooling system with a hydraulic cooling circuit. Such a hydraulic cooling system serves to dissipate the heat generated within an electrical machine due to electrical losses. Such a cooling system can have cooling channels within the rotor (rotor cooling channel) and / or stator (stator cooling channel) and, in particular, also a flow through the stator slots, through which a corresponding cooling fluid is guided to dissipate the heat.

[0027] The cooling fluid can particularly preferably be pumped through the hydraulic circuit by means of a pump. It is generally conceivable for a plurality of hydraulic circuits to be configured to cool the electric machine. In this case, it is highly preferred for the cooling channels of the stator to be connected to a hydraulic cooling circuit or to various cooling circuits of the cooling system. In particular, by connecting to multiple cooling circuits, it is possible to provide more precise cooling, since, for example, the temperature of the cooling fluid upon entering the cooling channels of the stator, the flow rate of the cooling fluid, or even the type of cooling fluid (oil, emulsion) can be adjusted.

[0028] The stator slots are preferably closed by a slot closure means so that the cooling fluid cannot flow from the stator slots into the air gap between the rotor and stator. The slot closure means is particularly preferably a slot closure wedge.

[0029] The stator may further comprise a hydraulic cooling system. In addition to direct slot cooling, the hydraulic cooling system particularly preferably also comprises a winding head cooling system, by means of which at least one winding head can be exposed to the cooling fluid, at least in sections.

[0030] The stator can be housed in a motor housing, which encloses the stator or the electric machine. A motor housing can also accommodate the control and power electronics. The motor housing can also be part of a cooling system for the electric machine and be designed such that cooling fluid can be supplied to the electric machine via the motor housing and / or heat can be dissipated to the outside via the housing surfaces. Furthermore, the motor housing protects the electric machine and any electronics from external influences.

[0031] A motor housing can, in particular, be formed from a metallic material. Advantageously, the motor housing can be formed from a metallic cast material, such as die-cast aluminum, die-cast magnesium, gray cast iron, or cast steel.

[0032] The electric machine can be powered by power electronics. The power electronics, which are preferably accommodated in an inverter housing, can be provided in particular for an electric machine of an electrically operated drive train of a motor vehicle. The power electronics is preferably a combination of various components which control or regulate a current to the electric machine of the axle drive train, preferably including the peripheral components required for this purpose, such as cooling elements or power supplies. In particular, the power electronics contains one or more power electronics components which are designed to control or regulate a current. These are particularly preferably one or more power switches, e.g. power transistors. The power electronics particularly preferably has more than two, particularly preferably three separate phases orCurrent paths, each with at least one dedicated power electronics component. The power electronics are preferably designed to control or regulate a power per phase with a peak power, preferably continuous power, of at least 100 W, preferably at least 1000 W, particularly preferably at least 10,000 W.

[0033] Advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically expedient manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, where further preferred embodiments of the invention are presented.

[0034] According to an advantageous embodiment of the invention, a radially outwardly extending, ring-shaped first wall section is formed on the first fluid guide section. This further improves fluid guidance, since at the upper region of the stator body, in the direction of gravity, the cooling fluid cannot flow axially over the first fluid guide section, but is forced by the first wall section in a circumferential flow direction around the winding head.

[0035] Preferably, the first fluid guide section covers an angle of 180-350°, preferably 200-270°, in the circumferential direction, which has proven to be particularly advantageous with regard to efficient fluid guidance and open winding head cooling.

[0036] Furthermore, it is particularly preferable for the first wall section to sweep an angle of 20-180°, preferably 30-60°, in the circumferential direction. This can also contribute to optimized fluid guidance and winding head cooling, since a sufficient amount of cooling fluid can be redirected from the upper regions of the stator in the direction of gravity to a circumferential flow direction. It is further preferred that the first wall section extends symmetrically to a plane perpendicular to the dividing plane between the upper half and the lower half, whereby a uniform cooling fluid distribution in the circumferential direction can be achieved across the first fluid guide section.It is also advantageous if the first fluid guide section runs symmetrically to a plane perpendicular to the dividing plane between the upper half and the lower half, which can also contribute to a particularly uniform cooling effect over the circumference.

[0037] According to a further preferred development of the invention, a radially inwardly extending, ring-shaped second wall section can also be formed on the second fluid guide section. This can provide a trough-like structure in the lower region of the stator, as seen in the direction of gravity, that partially collects the cooling fluid flowing down from the upper regions, as seen in the direction of gravity, and can direct it to a controlled discharge. This measure also leads to improved cooling of the winding head.

[0038] It has proven particularly advantageous for the second fluid guide section to cover an angle of 10-180°, preferably 90-160°, in the circumferential direction in order to provide efficient fluid guidance and open winding head cooling. It is also preferred for the first fluid passage opening to be positioned at the lowest point of the second fluid guide section in the direction of gravity.

[0039] In this context, it is furthermore particularly advantageous if the second wall section sweeps over an angle of 10-180°, preferably 90-160°, in the circumferential direction, as a result of which a sufficiently large absorption capacity can be provided for the trough-like region at the lower end of the stator in the direction of gravity, as a result of which the efficiency of the winding head cooling can be further optimized. In order to achieve a uniform cooling effect over the circumference, it can further be preferred if the second wall section runs symmetrically to a plane that is perpendicular to the parting plane between the upper half and the lower half. In order to further optimize the cooling performance in the circumferential direction, the second fluid guide section can also run symmetrically to a plane that is perpendicular to the parting plane between the upper half and the lower half.

[0040] To further optimize fluid guidance and winding head cooling, it can also be provided that the first fluid guide section and the second fluid guide section have two overlapping regions in the circumferential direction. This ensures that cooling fluid guided via the first fluid guide section and flowing down in the direction of gravity is reliably collected by the second fluid guide section and fed in a controlled manner to further wetting the winding head, without significant losses of cooling fluid occurring during the transition. Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that a second fluid passage opening is formed on the first wall section, via which the cooling fluid can be fed to a rolling bearing via a fluid path.This allows, for example, a fluid path to be coupled to a fluid path located at the top in the direction of gravity, through which the cooling fluid can then flow in the direction of gravity. The cooling fluid can be supplied to other components that need to be cooled or lubricated via the fluid path.

[0041] According to a further particularly preferred embodiment of the invention, it can be provided in this context that the fluid path is formed in a bearing plate which supports the rolling bearing, wherein the fluid path preferably passes through the rolling bearing for its lubrication and cooling.

[0042] Furthermore, the invention can also be further developed such that a further fluid passage is formed on each side of the first fluid passage in the circumferential direction, wherein the flow cross-section of the first fluid passage is larger than the flow cross-sections of the adjacent fluid passages in the circumferential direction. As a result, the outflow behavior of the collected cooling fluid from the region of the fluid guide ring located at the bottom in the direction of gravity can be discharged in a more uniform manner, which can also contribute to optimized cooling of the winding head. In this context, it can also be advantageous if the adjacent fluid passages in the circumferential direction are arranged symmetrically in the circumferential direction to the first fluid passage, whereby a cooling effect that is uniform in the circumferential direction can be achieved.The additional fluid passages preferably have flow cross-sections that decrease with increasing distance in the circumferential direction from the first fluid passage. This ensures that the largest volume flow exits at the first fluid passage, thus achieving the best possible cooling of the winding head at this position. In a likewise preferred embodiment of the invention, it can also be provided that the first fluid guide section, the second fluid guide section, the first wall section, and the second wall section are formed in one piece, in particular monolithically. This can further improve the ease of assembly of the fluid guide ring, since it can be attached to the stator body as a prefabricated component.In principle, however, it would also be possible to design the fluid guide ring in several parts, in particular to design the first fluid guide section and / or the second fluid guide section and / or the first wall section and / or the second wall section separately.

[0043] It may also be advantageous to further develop the invention such that the fluid guide ring is formed from a plastic, which can be particularly favorable in terms of manufacturing technology. In principle, however, it would also be possible to form the fluid guide ring from a metallic material, for example from sheet metal using a forming process. Of course, the fluid guide ring can also be formed from different materials; for example, the first fluid guide section and / or the second fluid guide section and / or the first wall section and / or the second wall section can be formed from a plastic, or the first fluid guide section and / or the second fluid guide section and / or the first wall section and / or the second wall section can be formed from a metal. The plastic can, in particular, also be a fiber-reinforced plastic, which can bring advantages with regard to vibration damping.

[0044] The object of the invention is further achieved by an electrical machine comprising a stator according to one of claims 1-8 and a rotor rotatably mounted relative to the stator

[0045] Finally, the object of the invention can also be achieved by an electric drive train of a motor vehicle comprising an electric machine according to claim 9. The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0046] It shows:

[0047] Figure 1 shows a motor vehicle with an electric drive train in a schematic representation,

[0048] Figure 2 shows an electrical machine in a cross-sectional view,

[0049] Figure 3 shows an electrical machine in a schematic

[0050] Axial section view,

[0051] Figure 4 shows a stator with a fluid guide ring and a bearing shield in an exploded view,

[0052] Figure 5 shows a stator with a fluid guide ring in a perspective view,

[0053] Figure 6 shows a stator with a fluid guide ring and a bearing plate in a perspective partial axial section,

[0054] Figure 7 shows a guide ring in a first perspective view,

[0055] Figure 8 shows a guide ring in a second perspective view.

[0056] Figures 2-6 show a stator 1 for an electrical machine 2, in particular for an electrical machine 2 within a drive train 3 of a motor vehicle 4, as also sketched in Figure 1. The electrical machine 2 is configured as a radial flux machine and comprises a hollow cylindrical stator 1 in which a rotor 34 is arranged, which is rotatably mounted relative to the stator 1, as can be clearly seen from Figures 2-3. The stator 1 comprises a stator body 5 with a plurality of stator teeth 6 arranged in a circumferentially distributed manner and stator slots 7 formed between the stator teeth 6 and extending in the axial direction through the stator body 5. Electrical conductors 8 of a stator winding 9 are arranged in the stator slots 7 and emerge from the end face of the stator body 5 at least to form a winding overhang 10. The stator slots 7 and / or the electrical conductors 8 are cooled directly by a cooling fluid 11.For this purpose, the stator slots 7 are closed by a slot closure means (not explicitly shown) to guide the cooling fluid 11 through the stator slots 7. The cooling fluid 11 can be guided through the stator slots 7, for example, by means of a fluid pump.

[0057] During operation of the electric machine 2, the winding head 10 can be exposed to the cooling fluid 11 flowing through the stator slots 7. The cooling fluid 11 then exits axially from the stator slots 7.

[0058] The stator body 5 has an upper half 12 and a lower half 13, viewed in the direction of gravity. Thus, in its installed position, the stator body 5 is divided into exactly an upper half 12 and a lower half 13, with the separation plane extending axially through the stator body 5. The two halves 12, 13 are thus essentially mirror-symmetrical at the separation plane.

[0059] Figures 3-6 clearly show that a fluid guide ring 15 is positioned on the cylindrical ring-like winding head 10. This fluid guide ring has a first fluid guide section 16, similar to a cylindrical ring section, whose outer diameter 17 is smaller than the inner diameter 18 of the winding head 10 and which axially overlaps with the winding head 10. This first fluid guide section 16 further extends in the circumferential direction of the fluid guide ring 15 completely through the upper half 12 of the stator body 5.

[0060] The fluid guide ring 15 further comprises a second fluid guide section 19 in the form of a cylindrical ring, the inner diameter 20 of which is larger than the outer diameter 21 of the winding head 10 and which has an axial overlap with the winding head 10. The second fluid guide section 19 further extends in the circumferential direction of the fluid guide ring 15 in sections through the lower half 13 of the stator body 5. The fluid guide section 19 further comprises a first fluid passage opening 22, from which the cooling fluid 11 can flow out by gravity.

[0061] The cooling fluid 11 from the upper half 12 of the stator 1 is thus guided downwards in the direction of gravity via the first fluid guide section 16 and then transferred by dripping or flowing off to the second fluid guide section 19, from where the cooling fluid 11 can then flow out through the first fluid passage opening 22.

[0062] The flow of the cooling fluid 11 can thus be specifically directed at the winding head 10 of the stator 1 with its direct slot cooling by the fluid guide ring 15 and the winding head cooling can thereby be optimized accordingly.

[0063] Even if it is not shown, it is nevertheless conceivable that the first fluid guide section 16 is also designed as a ring which is closed in the circumferential direction and which has at least one opening in its lower section in the direction of gravity, from which the cooling fluid 11 can emerge and be transferred to the second fluid guide section 19.

[0064] The first fluid guide section 16 is aligned symmetrically to a plane 33 perpendicular to the dividing plane between the upper half 12 and the lower half 13. A radially outwardly extending, ring-like first wall section 23 is formed on the first fluid guide section 16. The first wall section 23 sweeps an angle of 20-180°, preferably 30-60°, in the circumferential direction and is arranged symmetrically to a plane 33 perpendicular to the dividing plane between the upper half 12 and the lower half 13 on the first fluid guide section 16.

[0065] A radially inwardly extending, ring-section-like second wall section 24 is formed on the second fluid guide section 19. The second wall section 24 sweeps an angle of 10-180°, preferably 90-160°, in the circumferential direction and is positioned symmetrically to a plane 33 on the second fluid guide section 19 that is perpendicular to the dividing plane between the upper half 12 and the lower half 13. The first fluid passage opening 22 is arranged at the lowest point of the second fluid guide section 19 in the direction of gravity. The circumferentially adjacent fluid passage openings 29, 30 are aligned symmetrically in the circumferential direction to the first fluid passage opening 22. The second wall section 24 is formed integrally, in particular monolithically, with the first fluid guide section 16.The second wall section 24 runs symmetrically to a plane 33 perpendicular to the dividing plane between the upper half 12 and the lower half 13.

[0066] In the circumferential direction on both sides of the first fluid passage opening 22, a further fluid passage opening 29, 30 is formed, wherein the flow cross section of the first fluid passage opening 22 is larger than the flow cross sections of the circumferentially adjacent fluid passage openings 29, 30.

[0067] A second fluid passage opening 25 is formed on the first wall section 23, through which the cooling fluid 11 can be supplied to a rolling bearing 27 via a fluid path 26, which can be clearly seen from the combination of Figure 6 and Figure 3. The fluid path 26 is formed in a bearing plate 28, which supports the rolling bearing 27.

[0068] In the embodiment of the fluid guide ring 15 shown, as can also be seen in Figures 7-8, the first fluid guide section 16, the second fluid guide section 19, the first wall section 23 and the second wall section 24 are formed in one piece, in particular monolithically, from a plastic.

[0069] From Figures 7-8 it can also be clearly seen that the first fluid guide section 16 covers an angle of 180-350°, preferably 200-270°, in the circumferential direction and the second fluid guide section 19 covers an angle of 10-180°, preferably 90-160°, in the circumferential direction.

[0070] It can also be seen that the first fluid guide section 16 and the second fluid guide section 19 have two overlapping regions 31, 32 in the circumferential direction, which can promote the secure fluid transfer from the first fluid guide section 16 to the second fluid guide section 19.

[0071] The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be considered restrictive, but rather explanatory. The following claims are to be understood in such a way that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority.

[0072] List of reference symbols

[0073] 1 stator

[0074] 2 electric machine

[0075] 3 Drivetrain

[0076] 4 Motor vehicle

[0077] 5 Stator body

[0078] 6 stator teeth

[0079] 7 stator slots

[0080] 8 conductors

[0081] 9 Stator winding

[0082] 10 winding head

[0083] 11 Cooling fluid

[0084] 12 half

[0085] 13 half

[0086] 15 Fluid guide ring

[0087] 16 Fluid guide section

[0088] 17 diameters

[0089] 18 diameter

[0090] 19 Fluid guide section

[0091] 20 diameters

[0092] 21 diameters

[0093] 22 Fluid passage opening

[0094] 23 wall section

[0095] 24 wall section

[0096] 25 Fluid passage opening

[0097] 26 Fluid path

[0098] 27 rolling bearings

[0099] 28 Bearing shield

[0100] 29 Fluid passage opening

[0101] 30 Fluid passage opening

[0102] 31 Coverage area

[0103] 32 Coverage area

[0104] 33 Level

[0105] 34 Rotor

Claims

Claims 1 . Stator (1) for an electrical machine (2), in particular for an electrical machine (2) within a drive train (3) of a motor vehicle (4), comprising a stator body (5) with a plurality of circumferentially distributed stator teeth (6) and stator slots (7) formed between the stator teeth (6) and extending in the axial direction through the stator body (5), wherein electrical conductors (8) of a stator winding (9) are arranged in the stator slots (7), which emerge from the end face of the stator body (5) at least to form a winding head (10), wherein the winding head (10) can be acted upon by a cooling fluid (11) flowing through the stator slots (7) during operation of the electrical machine (2), and the stator body (5) has an upper half (12) and a lower half (13) viewed in the direction of gravity, characterized in that a fluid guide ring (15) is positioned on the cylindrical ring-like winding head (10),which has a first cylinder ring section-like fluid guide section (16), the outer diameter (17) of which is smaller than the inner diameter (18) of the winding head (10) and which has an axial overlap with the winding head (10) and which further extends in the circumferential direction of the fluid guide ring (15) at least through the upper half (12) of the stator body (5), wherein the fluid guide ring (15) further has a second cylinder ring section-like fluid guide section (19), the, inner diameter (20) is larger than the outer diameter (21) of the winding head (10) and which has an axial overlap with the winding head (10) and which further extends in the circumferential direction of the fluid guide ring (15) at least in sections through the lower half (13) of the stator body (5) and has a first fluid passage opening (22) from which cooling fluid (11) can flow out under the effect of gravity.

2. Stator (1) according to claim 1, characterized in that a radially outwardly extending, ring-section-like first wall section (23) is formed on the first fluid guide section (16).

3. Stator (1) according to claim 1 or 2, characterized in that a radially inwardly extending, ring-section-like second wall section (24) is formed on the second fluid guide section (19).

4. Stator (1) according to claim 2, characterized in that a second fluid passage opening (25) is formed on the first wall section (23), via which the cooling fluid (11) can be supplied to a rolling bearing (27) via a fluid path (26).

5. Stator (1) according to claim 4, characterized in that the fluid path (26) is formed in a bearing plate (28) which carries the rolling bearing (27).

6. Stator (1) according to one of the preceding claims, characterized in that in the circumferential direction on both sides of the first fluid passage opening (22) a further fluid passage opening (29, 30) is formed, wherein the flow cross section of the first fluid passage opening (22) is larger than the flow cross sections of the circumferentially adjacent fluid passage openings (29, 30).

7. Stator (1) according to one of the preceding claims, characterized in that the first fluid guide section (16), the second fluid guide section (19), the first wall section (23) and the second wall section (24) are formed in one piece, in particular monolithically.

8. Stator (1) according to one of the preceding claims, characterized in that the fluid guide ring (15) is formed from a plastic.

9. Electrical machine (2) comprising a stator (1) according to one of the preceding claims and a rotor (34) rotatably mounted relative to the stator (1) 10. Electric drive train (3) of a motor vehicle (4) comprising an electric machine (2) according to claim 9.

Images