Stator and electric machine

Abstract

The invention relates to a stator (1). The stator (1) has a cylindrical design with an inner diameter (17), into which a rotor (20) with an outer diameter (21) can be inserted, thereby forming a cylindrical air gap (22). The stator (1) has a plurality of stator teeth (5), and a cooling fluid (12) can flow through the stator (1) from at least one first end face (11). The first end face (11) is equipped with an attachment body (13) which extend away from the first end face at least partly in the axial direction. The stator (1) has a cylindrical fluid guide body (14) with an annular base (15) and an inner casing (16), which extends outwards axially from the base (15), and the stator also has an outer casing (26), which extend outwards axially from the base (15). The inner casing (16) has an inner diameter (18) which is greater than or equal to the outer diameter (21) of the rotor (20), and the inner casing (16) and the outer casing (26) of the fluid guide body (14) are fixed to the attachment body (13) by means of an adhesive connection.

Description

[0001] Stator and electrical machine

[0002] The present invention relates to a stator for an electrical machine, in particular within a drive train of a motor vehicle, wherein the stator is designed in the shape of a cylindrical ring with an inner diameter, in which a rotor with an outer diameter can be inserted to form a cylindrical ring-shaped air gap, and the stator has a plurality of stator teeth, which in the circumferential direction between adjacent stator teeth each define a stator slot extending in the radial direction and running axially through the stator, with two slot side walls and a slot base, into which a current-carrying winding comprising a plurality of conductors is inserted, wherein a cooling fluid can flow through the stator from at least a first end face, and a connecting body extending at least partially axially away from the first end face is arranged on the first end face.The invention further relates to an electrical machine.

[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] Electrical machines with a hollow cylindrical stator, i.e., internal rotor machines, and configured for use as traction drives in motor vehicles often have a stator winding with a rectangular cross-section to achieve high power density. In electrical machines intended for motor vehicle power, the stator windings are therefore typically designed as coil windings. For example, essentially U-shaped wire segments are inserted into the stator slots from one end face of the stator and then formed on an opposite end face of the stator and connected, for example, by welding.

[0010] The object of the invention is therefore to provide a stator for an electrical machine that can provide high power density and effective cooling. It is also the object of the invention to create a stator that is cost-effective to manufacture and easy to install while maintaining high operational reliability. It is also the object of the invention to provide an optimized electrical machine.

[0011] This object is achieved by a stator for an electric machine, in particular within a drive train of a motor vehicle, wherein the stator is designed in the shape of a cylindrical ring with an inner diameter, in which a rotor with an outer diameter can be inserted to form a cylindrical ring-shaped air gap, and the stator has a plurality of stator teeth, which in the circumferential direction between adjacent stator teeth each define a stator groove extending in the radial direction and extending in the axial direction through the stator, with two groove side walls and a groove base, into which a current-carrying winding comprising a plurality of conductors is inserted, wherein the stator can be flowed through by a cooling fluid from at least a first end face, and a connecting body extending at least partially axially away from the first end face is arranged on the first end face,wherein the stator comprises a cylindrical ring-shaped fluid guide body with an annular base and an inner shell extending axially from the base and an outer shell extending axially from the base, wherein the inner shell has an inner diameter that is greater than or equal to the outer diameter of the rotor, and wherein the inner shell and the outer shell of the fluid guide body are fixed to the connecting body by means of an adhesive connection,

[0012] This provides the advantage that the rotor can be realized particularly easily by axially inserting it into the stator, with the stator then already fully assembled and equipped with a fluid cooling system. Thus, the fluid guide body can first be connected to the stator's connection body using an easy-to-assemble adhesive process, thus assembling the stator's fluid cooling system. The rotor can then be axially inserted into the largely operational stator, simplifying assembly and production logistics.

[0013] Particularly preferably, the bond between the fluid guide body and the connecting body is oil-tight, so that, for example, additional seals such as O-rings can be dispensed with. To achieve this, a connecting groove can preferably provide defined bonding gaps as an adhesive joint, for example in a V shape. The adhesive is applied as a continuous bead over the entire circumference into the base of a connecting groove. This ensures that adhesive is present over the entire circumference. During assembly of the fluid guide element, the adhesive is then pressed into the connecting groove over the entire circumference by means of a connecting collar engaging in the connecting groove, thus creating a closed ring of adhesive in a connecting groove, so that an oil-tight bond can be achieved. This can in particular define a dry space inside the stator.Furthermore, the fluid guide body can preferably be positioned precisely in the circumferential direction relative to the connecting body by means of suitable centering means, so that, for example, a fluid connection of the fluid guide body can meet a corresponding counterbore without further tolerance compensation.

[0014] The winding inserted into the stator slots preferably emerges from the stator, forming a winding head on each of the two end faces of the stator, with at least one connecting body being molded into or onto the stator body. This provides the advantage that a molded-on connecting body can provide a number of different functions in a component manufactured by injection molding. These functions of the connecting body can be selected, for example, from the group of fixing functions, closure functions, insulation functions, and / or sealing functions.

[0015] In this context, it is particularly preferred that a plurality of individual laminations or lamination stacks of the stator body are fixed in position relative to one another by means of the connecting body. This eliminates the need for fixation / stabilization / packaging by means of baked enamel, clinching, and / or welding, since this is implemented by the connecting body.

[0016] A thermosetting plastic, such as an epoxy resin, could be used as the plastic for molding the connecting body, but other plastics are also conceivable. Preferably, the connecting body is molded from one plastic. It is also conceivable for the connecting body to be formed from several different plastics, for example, using a dual-injection molding process.

[0017] A connecting body is preferably formed in one piece. However, it is also conceivable for the connecting body to be formed in multiple parts, in which case it is further preferred for the multiple parts of the connecting body to be molded from the same plastic. In principle, it is conceivable for multiple connecting bodies to be present in or on the stator. It is highly preferred for the connecting body to be injection-molded in or on the stator body of the stator. This means that the connecting body was formed in or on the stator body during the injection-molding process and was not subsequently arranged as a separate component in or on the stator.

[0018] According to an advantageous embodiment of the invention, it can be provided that the stator slots each have slot side walls extending in the radial direction in cross-section and a slot base, wherein the connecting body completely covers the slot side walls and the slot base. The advantage of this embodiment is that by coating the side walls and the slot base with a plastic, the use of a separate insulating paper can be dispensed with. It is understood that the plastic has electrically insulating properties for this purpose. Furthermore, in this context, it is preferred that the connecting body has a substantially uniform layer thickness on the slot side walls and the slot base.The complete coverage of the side walls and the slot base also makes it possible to create a fluid seal between the stator slots and the stator body, allowing the stator to also have fluid cooling of the stator slots. Furthermore, the design of the connecting body on the slot side walls and the slot base can support the fixation of the stator laminations or stator lamination stacks.

[0019] According to a further preferred development of the invention, it can also be provided that the stator slots each have a slot opening extending radially in cross-section, with the connecting body closing the slot opening. This makes it possible to close the stator slots radially inward by the connecting body, and, for example, to dispense with the otherwise conventional slot closure wedges.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] For the purposes of this application, motor vehicles are defined as land vehicles that are propelled by mechanical power without being tied to railway tracks. A motor vehicle can, for example, be selected from the group of passenger cars (PCs), trucks (HGVs), mopeds, light motor vehicles, motorcycles, buses (KOMs), or tractors.

[0032] Further 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.

[0033] According to an advantageous embodiment of the invention, the inner diameter of the cylindrical annular fluid guide body can be greater than or equal to the inner diameter of the stator. The advantage of this embodiment is that a particularly large clearance can be provided for inserting the rotor, which also reduces the risk of damage to the fluid guide body during rotor assembly.

[0034] According to a further preferred development of the invention, the fluid guide body can also be provided with a fluid connection on its outer casing, extending radially outward from the outer casing. This makes it possible to realize a particularly convenient and accessible connection option for the fluid guide body, for example, to a cooling circuit.

[0035] Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the connecting body has a cylindrical ring-shaped inner connecting section extending axially out of the stator on the inner diameter of the stator, to which the inner shell of the fluid guide body is fixed by means of the adhesive connection, and / or the connecting body has a cylindrical ring-shaped outer connecting section extending axially out of the stator, to which the outer shell of the fluid guide body is fixed by means of the adhesive connection. The advantageous effect of this embodiment is based on the fact that a defined, in particular also circumferentially closed, adhesive connection can be provided.

[0036] According to a further particularly preferred embodiment of the invention, it can be provided that the outer connection section has a first connection groove into which a first connection collar of the outer casing engages, or the outer casing has a first connection groove into which a first connection collar of the outer connection section engages, wherein the adhesive connection is formed between the first connection groove and the first connection collar. This can in particular achieve the effect that the quality of the adhesive connection can be further improved by the connection grooves. The first connection groove can preferably be designed to be continuously closed. Accordingly, it is also preferred that the first connection collar is designed to be continuously closed. It can also be preferred that the first connection groove and the first connection collar are ring-segment-shaped or ring-shaped.

[0037] Furthermore, the invention can also be further developed in such a way that the inner connecting section has a circumferential second connecting groove into which a circumferential second connecting collar of the inner casing engages, or the inner casing has a circumferential second connecting groove into which a circumferential second connecting collar of the inner connecting section engages, wherein the adhesive connection is formed between the second connecting groove and the second connecting collar. Here, too, the connecting groove can contribute to an improvement of the adhesive connection. The second connecting groove can preferably be designed to be closed all the way around. Accordingly, it is also preferred that the second connecting collar is designed to be closed all the way around. It can also be preferred that the second connecting groove and the second connecting collar are designed to be ring-segment-shaped or ring-shaped.

[0038] According to a further preferred embodiment of the invention, the first connection groove can have a V-shaped contour in axial section, into which the first connection collar engages with a correspondingly shaped V-shaped contour, and / or the second connection groove can have a V-shaped contour in axial section, into which the second connection collar engages with a correspondingly shaped V-shaped contour. This enables precise adjustment of the bonding gap through axial displacement and thus a certain tolerance compensation.

[0039] In a likewise preferred embodiment of the invention, it can also be provided that first spacer ribs are formed on the first connection collar and / or the first connection groove, by means of which a first minimum adhesive gap between the connection collar and the first connection groove can be defined, and / or second spacer ribs are formed on the second connection collar and / or the second connection groove, by means of which a second minimum adhesive gap between the connection collar and the first connection groove can be defined. This makes it possible for the adhesive bond to provide a defined layer thickness and thus also load-bearing capacity.

[0040] It may also be advantageous to further develop the invention in such a way that a first centering means is formed on the outer casing, which engages with a corresponding second centering means of the connecting body in such a way that the fluid guide body is secured relative to the connecting body in the circumferential direction and / or in the radial direction. The advantage that can be realized in this way is that rotation of the fluid guide body relative to the connecting body can be prevented during assembly before the two parts form the bond. This prevents rotation of components that are already in contact with the bond.

[0041] According to a further preferred embodiment of the subject matter of the invention, the centering means can be arranged asymmetrically distributed over the circumference. This ensures that the two components can only be axially positioned relative to each other in their end positions in a predefined circumferential position.

[0042] The object of the invention is further achieved by an electric machine, in particular for a drive train of a motor vehicle, wherein the stator is designed in the manner of a cylindrical ring with an inner diameter in which a rotor with an outer diameter is rotatably mounted to form a cylindrical ring-shaped air gap, wherein the stator is designed according to one of claims 1-10.

[0043] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0044] It shows:

[0045] Figure 1 shows a motor vehicle with an electric axle drive train in a schematic representation,

[0046] Figure 2 shows an electrical machine in a cross-sectional view,

[0047] Figure 3 shows a stator in a perspective axial section view,

[0048] Figure 4 shows a first detailed view of an electrical machine with a bonded fluid guide body in an axial section view,

[0049] Figure 5 shows a detailed view of the outer shell of the fluid guide body in an axial sectional view, Figure 6 shows a detailed view of a first embodiment of an inner shell of the fluid guide body in an axial sectional view,

[0050] Figure 7 is a detailed view of a second embodiment of an inner shell of the fluid guide body in an axial sectional view,

[0051] Figure 8 shows a detailed view of the fluid connection of the fluid guide body in a partial sectional view,

[0052] Figure 9 A first detailed view of the connecting body with a centering means and a second detailed view of the fluid guide body with a centering means,

[0053] Figure 10 is a perspective view of the stator body with a connecting body,

[0054] Figure 11 is a perspective view of the fluid guide body.

[0055] Figure 2 shows a stator 1 for an electric machine 2 within a drive train 3 of a motor vehicle 4, as can also be seen by way of example in Figure 1. The stator 1 is designed in the shape of a cylindrical ring with an inner diameter 17, into which a rotor 20 with an outer diameter 21 can be inserted to form a cylindrical ring-shaped air gap 22. The stator 1 further has a plurality of stator teeth 5, which each define a stator slot 6 extending in the radial direction between adjacent stator teeth 5 and running axially through the stator 1, said stator slot having two slot side walls 7 and a slot base 8, into which a current-carrying winding 9 comprising a plurality of conductors 10 is inserted. In the configuration shown, the electric machine 2 is configured as an internal rotor.As shown in Figure 3, the stator 1 has a connecting body 13 on the first end face 11, which extends at least partially axially away from the first end face 11. This connecting body 13 in turn has a first cylindrical ring-like connecting section 23 which extends in the axial direction from the stator body of the stator 1 and runs radially below a winding overhang of the winding 9. In the embodiment shown, the connecting body 13 also has a second cylindrical ring-like connecting section 24 which extends in the axial direction from the stator body of the stator 1 and runs radially above the winding overhang of the winding 9. As a result, the winding overhang is enclosed by an annular space which is defined by the inner cylindrical ring-like connecting section 23 and the outer cylindrical ring-like connecting section 24.It is possible for the connecting sections 23, 24 to be formed in two pieces and have no physical connection to one another, but to be molded onto the stator body of the stator 1 using the same injection molding process. The connecting sections 23, 24 are formed from the same plastic. Figure 3 shows an embodiment in which a connecting body 13 is also formed on the end face of the stator 1 opposite the end face 11.

[0056] In the embodiment shown in Figure 3, the connecting body 13, molded from a plastic material, is injection-molded onto the end face 11 of the stator 1, for example, using a corresponding injection-molding process. The stator slots 6, with their slot side walls 7 and the respective slot base 8, are also correspondingly injection-molded, at least in sections, with a plastic coating that is formed monolithically with the connecting body 13.

[0057] As can be seen in particular from Figure 4, a cooling fluid 12 can flow through the stator 1 from at least a first end face 11. To supply the cooling fluid 12, the stator 1 has a cylindrical ring-shaped fluid guide body 14 with an annular base 15 and an inner shell 16 extending axially from the base 15 and an outer shell 26 extending axially from the base 15. In this design, the fluid guide body 14 is reminiscent of a donut baking pan. The inner shell 16 has an inner diameter 18 that is greater than or equal to the outer diameter 21 of the rotor 20, so that the rotor 20 can be inserted axially into the stator 1 from the end face 11.For this purpose, the inner diameter 18 of the cylindrical ring-shaped fluid guide body 14 can be designed to be greater than or equal to the inner diameter 17 of the stator 1, which also enables axial insertion of the rotor 20 during assembly of the electric machine 2. The connecting body 13 is molded onto and secured to the laminated core of the stator body of the stator 1. The fluid guide body 14 is thus adhesively bonded to this connecting body 13 via two coaxially extending cylindrical ring-shaped connecting sections 23, 24. The adhesive joints between the connecting body 13 and the fluid guide body 14 are oil-tight, so that, for example, O-rings can be dispensed with. The connecting body 13 and the fluid guide body 14 have centering means 35, 36 to position the two correctly in terms of rotation relative to one another, which will be explained in more detail later.

[0058] The fluid guide body 14 further has a fluid connection 19 on its outer shell 26, extending radially out of the outer shell 26. Through this connection, the cooling fluid 12 can be guided through the fluid guide body 14 and via the connecting body 13 into the stator slots 6, where it can accordingly cool the winding 9 of the stator 1. This is also referred to as direct slot cooling.

[0059] The inner shell 16 and the outer shell 26 of the fluid guide body 14 are fixed to the connecting body 13 by means of an adhesive bond. For this purpose, the connecting body 13 has a cylindrical ring-shaped inner connecting section 23 extending axially out of the stator 1 at the inner diameter 17 of the stator 1, to which the inner shell 16 of the fluid guide body 14 is fixed by means of the adhesive bond. Furthermore, the connecting body 13 has a cylindrical ring-shaped outer connecting section 24 extending axially out of the stator 1, to which the outer shell 26 of the fluid guide body 14 is also fixed by means of the adhesive bond.From Figure 5, it can be seen that the outer connection section 24 has a circumferential first connection groove 27, into which a circumferential first connection collar 28 of the outer shell 26 engages, wherein the adhesive connection is formed between the first connection groove 27 and the first connection collar 28. First spacer ribs 32 are formed on the first connection collar 28 and / or the first connection groove 27, by means of which a first minimum adhesive gap 33 can be defined between the connection collar 28 and the first connection groove 27. Figure 5 thus shows the outer bond, which has a similar V-shaped connection groove 27 to the inner bond, which will be explained below. The fluid guide body 14 and the connecting body 13 have an annular stop 39 extending radially above the minimum adhesive gap 33, by means of which the axial position of the two components relative to each other is defined.

[0060] A precise adjustment of the adhesive gap and thus a certain tolerance compensation through axial positioning of the fluid guide body 14 relative to the connecting body 13 can also be achieved in that the first connecting groove 27 has a V-shaped contour in axial section, into which the first connecting collar 28 engages with a correspondingly shaped V-shaped contour. The same applies to the second connecting groove 31, which also has a V-shaped contour in axial section, into which the second connecting collar 30 engages with a correspondingly shaped V-shaped contour. This creates, as shown in Figures 5-6, V-shaped adhesive grooves with a first axially extending groove section, followed by a radially extending groove section, followed by a second axially extending groove section.

[0061] Figures 6-7 show two embodiments of inner connecting sections 23, wherein in the inner connecting section 23, the inner shell 16 in each case has a circumferential second connecting groove 31, into which a circumferential second connecting collar 30 of the inner connecting section 23 engages, wherein the adhesive connection is then formed between the second connecting groove 31 and the second connecting collar 30. Second spacer ribs 32 are also formed on the second connecting collar 30 and / or the second connecting groove 31, by means of which a second minimum adhesive gap 34 can be defined between the connecting collar 30 and the first connecting groove 31.

[0062] Figure 6 shows a detailed view of a first embodiment of the internal bond. End faces on the connecting body 13 and on the fluid guide body 14 serve as axial stops 37, 39. The spacer ribs 32 were provided on the fluid guide body 14 to form a precisely defined minimum bonding gap 34, which is necessary for the bond to have the designed strength. The bonding gap extending in the axial direction is uninterrupted in both the circumferential and axial directions and is not impaired by spacer ribs 32. This ensures the sealing of the bond. The spacer ribs 32 at the bonding gaps extending in the axial direction ensure, in particular, the necessary strength of the bond, while the radially extending bonding gap primarily ensures sealing.Because the spacer ribs 32 of the fluid guide body 14 can come into contact with the surface of the connecting body 13, the tightness at these axially extending adhesive gaps cannot always be guaranteed.

[0063] In this embodiment of Figure 6, the inner diameter of the fluid guide body 14 is also larger than the outer diameter 21 of the rotor 20 to ensure its assembly by axial insertion into the stator 1. The air gap 22 between the rotor 20 and the stator 1 not only serves as a clearance during assembly, but also compensates for the deformation of the rotor 20 resulting from centrifugal force and other tolerances. However, since the rotor 20 does not lie and rotate within the fluid guide body 14 during operation of the electric machine 2, only the clearance is required for assembly. The inner diameter 18 of the fluid guide body 14 can therefore also be smaller than the inner diameter 17 of the stator 1. This configuration is shown in Figures 4 and 6.

[0064] Depending on the design of the electrical machine 2, the play between the rotor 20 and the stator 1 can be larger or smaller. However, with closely mounted rotors 20, the fluid guide body 14 must have an inner diameter 18 that is not significantly smaller than the inner diameter 17 of the stator 1. This is achieved by the design of the internal bonding shown in Figure 7. The lower side of the V-shaped connecting groove 31 of the fluid guide body 14 has been removed from the design variant known from Figure 6, whereby the bonding principle remains unchanged. However, here the adhesive is no longer enclosed in the V-shaped connecting groove 31, which may make the bonding process more difficult to manufacture. However, this solution also works with very narrow air gaps between the rotor 20 and the stator 1. The V-shaped connecting groove 31 from Figure 6 has the advantage, due to its geometry, that the adhesive can be better forced oris subjected to pressure. This pressure is a prerequisite for creating optimal bonding.

[0065] Figures 8-9 show that a first centering means 35 is formed on the outer casing 26, which engages in a corresponding second centering means 36 of the connecting body 13 in such a way that the fluid guide body 14 is fixed relative to the connecting body 13 in the circumferential direction and / or in the radial direction.

[0066] During assembly of the fluid guide body 14, it must first engage a corresponding slot-like centering means 36 in the connecting body 13 via a radially inwardly projecting centering means 35, so that the adhesive joints can also meet their connection grooves 27, 31 in a second step. This sequence is necessary to ensure optimal bonding. If the two contact surfaces of the two adhesive joints are already in contact before rotational positioning, these surfaces would have to slide towards each other due to the rotation of the fluid guide body 14 during assembly, which could impair the adhesive layer.

[0067] The adhesive connection is oil-tight in the illustrated embodiments. To ensure this, the adhesive layer must not be damaged during assembly of the fluid guide body 14. If the centering means 35 of the fluid guide body 14 does not immediately engage its corresponding centering means 36 on the connecting body 13, the fluid guide body 14 could easily tip over due to the applied axial joining force, and the other side of the section of the fluid guide body 14 to be bonded could already strike the corresponding connecting groove on the connecting body 13. This could then "interrupt" the adhesive layer and thus cause it to leak. Therefore, it is preferable to arrange several pairs of corresponding centering means 35, 36 distributed over the circumference of the stator 1.In Figures 10-11, three centering means 35, 36 are arranged asymmetrically around the circumference, so that the fluid guide body 14 can only be mounted in a defined circumferential position relative to the connecting body 13, which corresponds to a Poka Yoke solution.

[0068] As long as the paired centering means 35, 36 are not arranged in their defined circumferential joining position relative to one another, the section of the fluid guide body 14 to be bonded does not come into contact with the V-shaped connecting grooves 27, 31 of the connecting body 13. Thus, the adhesive layer remains uninterrupted. Figure 10 shows a possible arrangement of the slot-like centering means 36 on the connecting body 13, where the slots are rotated by 105, 120, and 135° relative to one another. A solution with only one slot-like centering means 36 is also conceivable, although in this case, assembly using an auxiliary device is preferable to prevent tilting and thus contact of the sealing surfaces in the two V-grooves before rotational positioning.

[0069] 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 as meaning 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. List of reference symbols

[0070] 1 stator

[0071] 2 electric machine

[0072] 3 Drivetrain

[0073] 4 Motor vehicle

[0074] 5 stator teeth

[0075] 6 Stator slot

[0076] 7 groove side walls

[0077] 8 Groove base

[0078] 9 winding

[0079] 10 ladders

[0080] 11 Front side

[0081] 12 Cooling fluid

[0082] 13 connecting bodies

[0083] 14 fluid guide bodies

[0084] 15 Floor

[0085] 16 inner jacket

[0086] 17 inner diameter

[0087] 18 inner diameter

[0088] 19 Fluid connection

[0089] 20 rotors

[0090] 21 outer diameter

[0091] 22 Air gap

[0092] 23 connecting section

[0093] 24 connecting section

[0094] 26 outer shell

[0095] 27 Connection groove

[0096] 28 connection collars

[0097] 30 connection collars

[0098] 31 Connection groove

[0099] 32 spacer ribs

[0100] 33 Minimum adhesive gap Minimum adhesive gap Centering means Centering means Stop Stop

Claims

Claims 1. Stator (1) for an electrical machine (2), in particular within a drive train (3) of a motor vehicle (4), wherein the stator (1) is designed in the manner of a cylindrical ring with an inner diameter (17), in which a rotor (20) with an outer diameter (21) can be inserted to form a cylindrical ring-shaped air gap (22), and the stator (1) has a plurality of stator teeth (5), which in the circumferential direction between adjacent stator teeth (5) each define a stator groove (6) extending in the radial direction and extending in the axial direction through the stator (1), with two groove side walls (7) and a groove base (8), into which a current-carrying winding (9) comprising a plurality of conductors (10) is inserted, wherein the stator (1 ) is provided from at least one first end face (11) through which a cooling fluid (12) can flow, and on the first end face (11) a connecting body (13) extending at least partially axially away from the first end face is arranged, characterized in that the stator (1) has a cylindrical ring-shaped fluid guide body (14) with an annular base (15) and an inner shell (16) extending axially from the base (15) and an outer shell (26) extending axially from the base (15), wherein the inner shell (16) has an inner diameter (18) which is greater than or equal to the outer diameter (21) of the rotor (20), and wherein the inner shell (16) and the outer shell (26) of the fluid guide body (14) are fixed to the connecting body (13) by means of an adhesive connection 2. Stator (1) according to claim 1, characterized in that the inner diameter (18) of the cylindrical ring-shaped fluid guide body (14) is greater than or equal to the inner diameter (17) of the stator (1).

3. Stator (1) according to claim 1 or 2, characterized in that the fluid guide body (14) has on its outer casing (26) a fluid connection (19) extending in the radial direction out of the outer casing (26).

4. Stator (1) according to one of the preceding claims, characterized in that the connecting body (13) has, on the inner diameter (17) of the stator (1), a cylindrical ring-shaped inner connecting section (23) extending axially out of the stator (1), to which the inner shell (16) of the fluid guide body (14) is fixed by means of the adhesive connection and / or the connecting body (13) has a cylindrical ring-shaped outer connecting section (24) extending axially out of the stator (1), to which the outer shell (26) of the fluid guide body (14) is fixed by means of the adhesive connection.

5. Stator (1) according to claim 4, characterized in that the outer connecting section (24) has a first connecting groove (27) into which a first connecting collar (28) of the outer casing (26) engages or the outer casing (26) has a first connecting groove (27) into which a first connecting collar (28) of the outer connecting section (24) engages, wherein the adhesive connection is formed between the first connecting groove (27) and the first connecting collar (28).

6. Stator (1) according to claim 4 or 5, characterized in that the inner connecting section (23) has a second connecting groove (31) into which a second connecting collar (30) of the inner shell (16) engages or the inner shell (16) has a second connecting groove (31) into which a second connecting collar (30) of the inner connecting section (23) engages, wherein the adhesive connection is formed between the second connecting groove (31) and the second connecting collar (30).

7. Stator (1) according to claim 5 or 6, characterized in that the first connection groove (27) has a V-shaped contour in axial section, into which the first connection collar (28) engages with a correspondingly shaped V-shaped contour and / or the second connection groove (31) has a V-shaped contour in axial section, into which the second connection collar (30) engages with a correspondingly shaped V-shaped contour.

8. Stator (1) according to one of claims 5-7, characterized in that first spacer ribs (32) are formed on the first connection collar (28) and / or the first connection groove (27), by means of which a first Minimum adhesive gap (33) between the connecting collar (28) and the first connecting groove (27) can be defined and / or second spacer ribs (32) are formed on the second connection collar (30) and / or the second connection groove (31), by means of which a second minimum adhesive gap (34) between the connection collar (30) and the first connection groove (31) can be defined.

9. Stator (1) according to one of the claims, characterized in that a first centering means (35) is formed on the outer casing (26) which engages in a corresponding second centering means (36) of the connecting body (13) in such a way that the fluid guide body (14) is fixed relative to the connecting body (13) in the circumferential direction and / or in the radial direction.

10. Stator (1) according to claim 9, characterized in that the centering means (35,36) are arranged distributed asymmetrically over the circumference.

11. Electrical machine (2), in particular for a drive train (3) of a motor vehicle (4), wherein the stator (1) is designed in the manner of a cylindrical ring with an inner diameter (17), in which a rotor (20) with an outer diameter (21) is rotatably mounted to form a cylindrical ring-shaped air gap (22), characterized in that the stator (1) is designed according to one of claims 1-10.

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