CN112928855A

CN112928855A - Cooling system, electric vehicle, electric drive unit and method for cooling same

Info

Publication number: CN112928855A
Application number: CN202011413290.4A
Authority: CN
Inventors: D·埃伦伯格
Original assignee: Witzenmann GmbH
Current assignee: Witzenmann GmbH
Priority date: 2019-12-06
Filing date: 2020-12-04
Publication date: 2021-06-08
Also published as: FR3104312B1; DE102019133363A1; FR3104312A1

Abstract

The invention relates to a cooling system (1), in particular for a drive motor (M) in an electric vehicle (F), having a cooling sleeve (2) with a longitudinal axis (3) and a heat-conducting structure (4), the cooling sleeve (2) enclosing the heat-conducting structure (4) in a region along the longitudinal axis (3), whereby a cooling channel (5) is formed between the cooling sleeve (2) and the heat-conducting structure (4) in order to guide a cooling fluid (6) in the cooling channel, the heat-conducting structure (4) being configured and defined for accommodating a first heat source (7), in particular a stator of the drive motor (M), in the region for the electric vehicle (F). The heat conducting structure (4) is designed for thermally conducting contact with a second heat source (8), in particular power electronics in an electric vehicle (F) for driving an electric motor (M), which second heat source is arranged axially opposite the first heat source (7) along the longitudinal axis (3).

Description

Cooling system, electric vehicle, electric drive unit and method for cooling same

Technical Field

The invention relates to a cooling system, in particular for a drive motor of an electric vehicle, having a cooling sleeve with a longitudinal axis, which surrounds a heat conducting structure in a region along the longitudinal axis, whereby a cooling channel is formed between the cooling sleeve and the heat conducting structure for conducting a cooling fluid therein, and having a heat conducting structure which is designed and intended for accommodating a first heat source in the region, in particular a stator of the drive motor in the electric vehicle, according to the preamble of claim 1.

The invention furthermore relates to an electric drive unit according to claim 33, an electric vehicle according to claim 34 and a method for cooling an electric drive unit according to claim 35.

Background

Cooling systems of the type mentioned are known from the prior art and serve to dissipate heat formed during operation of certain devices, in particular in the electric machine or its peripheral, fluid-conducting components, and to prevent damage to the device to be cooled.

In particular, an electric motor that can be used as a drive motor of an electric vehicle may have a plurality of heat sources. Such a first heat source may be a stator of the electric machine, which is substantially hollow-cylindrical in shape and is arranged along the longitudinal axis of the electric machine. The stator generally includes a stator lamination stack and electrical conductors configured to generate a moving magnetic field when an electrical current is generated. The moving magnetic field in turn moves a rotor, which is disposed in an interior region of the stator. Due to the flow of the current, the electrical conductor and the stator may heat themselves, which may result in reduced efficiency. Furthermore, overheating of the stator may lead to irreversible damage and even to complete failure of the machine.

If the first heat source is surrounded by a heat-conducting structure, in particular a sleeve-shaped stator carrier as is usually used in known electrical machines, the heat released by the first heat source can be dissipated via the aforementioned heat-conducting structure. By additionally providing a cooling sleeve on the periphery of the heat conducting structure, cooling channels can be formed which are adapted to guide a cooling fluid over the heat conducting structure and thereby enhance the cooling effect. Such a cooling jacket is known from DE 102018109420 a 1.

If the device to be cooled has a further heat source, in particular an inverter or other power electronics, the heat released by the further heat source must also be conducted away. If a first cooling system with a heat-conducting structure and a cooling sleeve has been provided in the region of the first heat source, this serves in the known arrangement to arrange the second heat source outside the cooling sleeve, so that two heat flows are transferred into the cooling fluid. Such an arrangement is likewise known from DE 102018109420 a 1.

However, the arrangement of the second heat source on the outer circumference of the cooling jacket results in a radial increase in the required installation space, which is often limited, in particular in vehicles. This can result in that, in this arrangement, the cooling jacket must not exceed the maximum permitted outer diameter. The amount of available cooling fluid that can be guided in the cooling channel is thereby also limited. Since the transferable heat flow is directly related to the quantity of cooling fluid, the available radial installation space is a decisive factor in the cooling effect achievable by the cooling system.

Disclosure of Invention

It is therefore an object of the present invention to improve the cooling effect of a cooling system, in particular for cooling an electric machine. The object of the invention is also to provide an electric drive unit and an electric vehicle with a cooling system which has an improved cooling effect. Finally, it is an object of the invention to provide a method for cooling an electric drive unit, with which an improved cooling effect can be achieved.

According to the invention, the object is achieved by a cooling system having the features of claim 1, by an electric drive unit having the features of claim 33, by an electric vehicle having the features of claim 34 and by a method having the features of claim 35. Advantageous embodiments are the subject matter of the respective dependent claims.

The invention provides a cooling system, in particular for a drive motor in an electric vehicle, having a cooling sleeve with a longitudinal axis, which surrounds a heat-conducting structure in a region along the longitudinal axis, whereby a cooling channel is formed between the cooling sleeve and the heat-conducting structure for guiding a cooling fluid in the cooling channel, and having a heat-conducting structure which is configured and defined for accommodating a first heat source, in particular a stator of a drive motor in an electric vehicle, in the region. The heat conducting structure is configured for thermally conducting contact with a second heat source, in particular power electronics for driving an electric motor in an electric vehicle, which is arranged axially opposite the first heat source along the longitudinal axis.

Furthermore, the invention provides an electric drive unit, in particular for an electric vehicle. Such a vehicle accordingly has an electric machine comprising a rotor, a stator carrier, power electronics and a cooling system according to the invention, wherein the stator carrier is configured as the heat conducting structure.

Furthermore, the invention also provides an electric vehicle having an electric drive unit which comprises a cooling system according to the invention.

Furthermore, the invention provides a method for cooling an electric drive unit, the method providing a cooling system according to the invention, in which method: the cooling fluid is tempered to an inlet temperature and delivered to the cooling channel. The first heat source and the second heat source respectively transfer heat to the heat conducting structure, and the heat conducting structure transfers the heat to the cooling fluid. The cooling fluid is then conveyed out of the cooling channel.

The cooling system according to the invention achieves an improved cooling effect with respect to known cooling systems. This is achieved by: in the known cooling system, the installation space occupied by the second heat source, which is arranged radially with respect to the cooling jacket, can now be used to form the cooling jacket itself. The second heat source, in particular the power electronics, is here arranged axially along the longitudinal axis of the cooling sleeve relative to the first heat source, in particular the stator. The heat conducting structure is designed for thermally contacting the first heat source and the second heat source and for conducting heat away therefrom.

The cooling channel is preferably formed by a cavity arranged between the cooling sleeve and the heat conducting structure. The geometry of the cooling channel is determined here at least in part by the inner contour of the cooling sleeve, whereby the cooling sleeve can be designed for guiding a cooling fluid along a determined path. In particular, the inner contour of the cooling sleeve can have recesses (wave troughs or wave crests), grooves or slots which are configured along and/or transversely to the longitudinal axis of the cooling sleeve in order to form cooling channels thereby in cooperation with the surface of the heat-conducting structure, which cooling channels accordingly likewise extend along and/or transversely to the longitudinal axis, preferably helically.

Within the scope of the invention, the cooling channel has a different, in particular shorter, structural length along its longitudinal axis than the heat conducting structure. In particular, it is possible to arrange only the first heat source in the region along the longitudinal axis of the cooling sleeve, while the second heat source is not directly surrounded by the cooling sleeve. In this case, the heat flow of the second heat source first flows along the heat conducting structure into the region in which the cooling sleeve is arranged and is absorbed and carried away by the cooling fluid there.

By arranging the first and second heat sources in the axial direction, it is possible to increase the size of the cooling channel itself, in particular in the radial direction (i.e. transversely to the longitudinal axis) and thus to achieve a greater volume flow of cooling fluid. Alternatively or additionally, the necessary radial installation space can be reduced when the cooling jackets are the same size or the cooling channels are the same size, which is advantageous in particular in vehicle construction. Since the heat conducting structure is at least partially also used for thermally conductive contact with the first heat source, a high degree of functional integration is achieved. In particular, the manufacturing costs of the cooling system according to the invention can thereby be reduced.

In a preferred design, the cooling system comprises a heat conducting structure configured and defined for at least partially accommodating the second heat source

Due to the fact that the heat conduction structure capable of accommodating the first heat source and the second heat source is arranged, the advantage of high function integration degree is achieved. The heat-conducting structure can be designed as a stator carrier of the electric machine, preferably in such a way that only one component is required to accommodate the first and second heat sources and to dissipate the heat of the first and second heat sources. In particular, an additional housing for enclosing the second heat source is thus no longer required. Thus, some time consuming and costly manufacturing and assembly steps are eliminated in the manufacture of the cooling system.

In a further preferred embodiment, the heat conducting structure comprises a stator bearing for the drive motor, in particular a sleeve-shaped stator bearing.

Such stator supports are known components of electric machines and are customary in the art and serve both for enclosing and for supporting the stator. The stator carrier is usually sleeve-shaped and made of a metallic material and has a (cylindrical) outer surface and an inner surface. The outer surface may be particularly adapted for connection with a cooling jacket, whereby cooling channels may be formed. The stator can thus satisfy all the basic requirements set forth for a heat-conducting structure with which both the first heat source and the second heat source can be contacted in a heat-conducting manner. Thereby, the need for providing another component for forming the heat conducting structure may be completely eliminated, which means that the manufacturing costs may be reduced.

In a further preferred embodiment, the cooling sleeve is at least partially corrugated and is preferably made of a metallic material, the cooling channel having at least partially a cooling channel geometry corresponding to the corrugated geometry of the cooling sleeve.

The corrugated design of the cooling sleeve makes it possible to form a larger surface area on the outer surface of the cooling sleeve than a cooling sleeve designed cylindrically. This intensifies the possible cooling effect, which can be associated with a lower ambient temperature in the region outside the cooling jacket. In particular, the corrugation can be embodied by designing the cooling sleeve as a corrugated tube or as an (annular) bellows. In this way, a defined deformability of the cooling jacket, in particular transverse to its longitudinal axis, can be achieved.

Furthermore, the cooling jacket, which is designed as a bellows or as an (annular) bellows, can be of variable length, so that heat-conducting structures of different lengths can be enclosed by the single structural form of the bellows-type cooling jacket. In order to manufacture such a cooling jacket from thin metal sheets, a relatively economical and well-controllable forming process can be used. The resulting cooling jacket is here light in weight, which is advantageous in particular in vehicle manufacture. In particular in electric vehicles, the low weight has an advantageous effect on the cooling power required by the cooling system, since only a small mass has to be accelerated by the electric drive and therefore only a small torque has to be provided by the electric machine. These are in turn associated with low currents, which is why at least the first heat source in the form of a stator transfers less heat to the cooling system.

In a further preferred embodiment, the cooling channel is at least partially formed in a spiral or screw-thread shape along and/or around the longitudinal axis.

This spiral design of the cooling channel brings the advantage that the cooling fluid can be guided both over the circumference of the heat-conducting structure and over the length of the cooling jacket. Such a helical trend of the cooling channel may have a pitch which is determined structurally. Together with the nominal flow rate of the cooling fluid, the time during which a certain amount of heat is introduced into the cooling fluid over a period of time can be determined at least in part by the pitch. Furthermore, the pitch of the helical cooling channels may interact with the diameter of the cooling channels. The spiral-shaped formation of the cooling channel thus achieves overall adjustability with good cooling effect.

In a preferred embodiment, the cooling jacket is connected in a material-locking manner to the heat conducting structure in at least one joining region, in particular to seal the cooling channel in the joining region.

The interlocking connection of the cooling sleeve to the heat-conducting structural material can be effected in one or more joining regions, which can be distributed uniformly or non-uniformly over the longitudinal axis. In the case of a corrugated cooling sleeve, in particular the regions with a smaller cross section (wave troughs) are suitable for contacting the outside of the heat-conducting structure and are soldered, bonded or welded to the heat-conducting structure in these regions. In this way, a defined individual region of the cooling channel can be realized by the gas-tight or fluid-tight connection of the cooling jacket to the heat-conducting structure, so that mixing of the cooling fluids of adjacent regions can be avoided and a correspondingly reduced cooling effect can be avoided.

In a further preferred embodiment, the heat conducting structure comprises a bearing shield, in particular for a drive motor in an electric vehicle, which is arranged between the first heat source and the second heat source on the longitudinal axis.

The bearing shield is a known component, in particular in electrical machines. The bearing shield serves to hold a bearing, in particular a rolling bearing, on which a movable part of an electric machine, in particular a rotor or an output shaft, can be positioned and supported. The applicant has realised in a particularly advantageous manner that, in addition to the function of the bearing shield as a bearing seat, the heat-conducting properties of the bearing shield are utilised as part of a cooling system. This can be realized in the form of a heat-conducting connection between the bearing shield and the stator carrier, or in such a way that the bearing shield has a structurally designed, heat-conducting element, by means of which the bearing shield can be connected to the heat-conducting structure. The arrangement of the bearing shield between the first heat source, which may be configured as a stator, and the second heat source, which may be configured as power electronics, brings the advantage that both the first heat source and the second heat source can transfer the heat flow to the cooling fluid via the bearing shield, which forms part of the heat conducting structure. In other words, the bearing shield may form an integral part of the heat conducting structure.

In a further preferred embodiment, the bearing shield has at least one axial through-opening which is provided and configured for contacting the first heat source and/or the second heat source, in particular for electrically contacting the first heat source and/or the second heat source, for example by means of a cable which is guided through the axial through-opening.

The axial through-hole for contacting the first heat source and the second heat source achieves the advantage of achieving a high degree of functional integration in the bearing shield. The bearing shield, in addition to its function as a force-and heat-transfer element, also makes it possible to position conductors, in particular electrical conductors, in a defined and reliable manner. This is particularly advantageous when the first and/or second heat source are shaken or have an unpredictable relative movement with respect to each other, as said shaking or relative movement may damage the contact between the heat sources or the connection thereof to the heat sources may be released. The axial through-hole can preferably contain a seal or a tension release element in order to achieve the advantages described to a particularly great extent. Furthermore, the axial through-hole also offers the possibility of making the contact only within the inner space sealed by the heat-conducting structure. In particular, the electrical contacts can thereby be protected from the effects of the external environment, so that a high service life of such contacts can be achieved during operation.

In a further preferred embodiment, the bearing shield is at least partially formed by molding, in particular by deep-drawing and/or by forming, in particular by casting or by generative production.

The bearing shield is configured in a profiled manner, in particular a deep-drawn part, which brings advantages in terms of component weight, in particular when the bearing shield is configured as a plate part or plate component. As explained above, the low component weight has the effect that the necessary cooling power is favorably influenced in the electric vehicle.

By producing the bearing shield as a single piece, in particular by means of a cast molding, a high component rigidity can be achieved, as a result of which the cooling system as a whole is designed to be only slightly deformable and therefore in particular already existing joining points, such as welds or screw connections, are subjected to only small loads. Furthermore, in particular by using casting cores or using a generative method, cavities can be formed which can have a favorable effect on the achievable cooling effect and also on the weight of the bearing shield.

It is also within the scope of the invention for the bearing shield to be constructed from a combination of deformation-molded and prototype-molded components. Thereby, the characteristic advantages of both manufacturing method types can be utilized simultaneously.

In a further preferred embodiment, the bearing shield is designed for thermally conductive contact with the second heat source in that the bearing shield is designed to at least partially correspond to the geometry of the second heat source, i.e. in particular to be partially complementary to the shape of the second heat source.

By configuring the bearing shield with a geometry that is adapted to the geometry of the second heat source, the surface available for conducting heat from the second heat source via the bearing shield or the heat conducting structure to the cooling fluid may be enlarged. Accordingly, more heat can be introduced into the cooling system, so that the cooling effect of the cooling system as a whole can be improved.

In a further preferred embodiment, the second heat source is connected to the bearing shield by a thermally conductive intermediate layer, in particular by a thermally conductive paste.

By introducing a thermally conductive intermediate layer, in particular in the form of a thermally conductive paste, the contact surface between the second heat source and the bearing shield can be enlarged without the geometry of the two components having to be adapted to one another in a special manner. This is particularly advantageous in particular when the second heat source is a power electronic component which comprises an electronic element which, due to the structural form, has a geometry which cannot be easily adapted to the external conditions. This makes it possible to increase the cooling effect without structural adaptation.

In a preferred embodiment, the second heat source is arranged on a support plate which is mechanically connected, in particular detachably connected, to the bearing shield, preferably by means of screws, and most preferably on the side of the bearing shield facing away from the first heat source. The support plate may be a circuit board or the like.

By providing the second heat source on the carrier plate, there is the advantage of a functional separation between the heat-conducting connection and the mechanical connection. The support plate can be fastened to the bearing shield by means of a screw connection, i.e. at a location of the bearing shield having a large wall thickness, while the second heat source can be arranged at a location of the bearing shield having only a relatively small wall thickness. The respective advantages are thereby obtained for the mechanical and thermally conductive connection of the heat source to the bearing shield. Furthermore, the arrangement of the second heat source on the carrier plate facilitates the mounting on the cooling system, since the second heat source can be arranged on the carrier plate in a preceding assembly step, in order to subsequently mount it directly on the bearing shield with little operational effort.

In a further preferred embodiment, the heat conducting structure has radial through-openings, with which the cooling channels are connected in a fluid-conducting manner.

By forming the radial through-openings, the cooling fluid can be conducted from the outer region of the heat conducting structure into the inner region thereof, whereby the heat flow to be conducted can be branched off in particular from the interior of the electric machine, so that in this way different spatially separated regions can be cooled.

In a further preferred embodiment, the bearing shield comprises a flow-conducting cooling channel continuation, which is directly or indirectly flow-conducting connected to the cooling channel.

The cooling channel continuation is configured such that the cooling fluid provides an additional fluid path, which may be formed completely or partially in or on the bearing shield. With the fluid path, the flow-guiding area of the cooling system can be physically or geometrically enlarged, whereby a larger amount of cooling fluid can be directed to the first and second heat sources. The cooling effect of the cooling system as a whole can thereby be increased.

It is within the scope of the invention that the shape and position of the cooling channel extension are not limited to a specific design. Instead, the cooling channel continuation can be a group of individual flow-conducting channels which are in flow-conducting connection with the cooling channel, or the cooling channel continuation can also be a closed cavity into which the cooling fluid flows from the cooling channel, flows around in the cavity and flows out again from the cavity.

In any case, therefore, the bearing shield and, if appropriate, further components, such as bearings, shafts or the like, which are arranged in or on the bearing shield, can be cooled in a targeted manner, which may be advantageous in operation.

In a further preferred embodiment, the cooling channel continuation is formed integrally within the bearing shield.

The integral formation of the cooling channel continuation inside the bearing shield has the advantage of a high degree of functional integration. The cooling channel continuation can be formed already during the production by the core when the bearing shield is formed as a cast component or can be produced by a subsequent cutting production step in which the cooling channel continuation is drilled or milled into the bearing shield. One or more complex spatial trends of the cooling channel continuation can likewise be created by the generative manufacturing process. By the continuous, integral formation of the cooling channel, sealing surfaces which may be damaged during assembly or operation of the cooling system can be dispensed with. Thereby, the risk of leakage of the cooling fluid is reduced and the achievable service life of the cooling system is increased.

In a further preferred embodiment, the cooling channel continuation comprises at least one first partial continuation and at least one second partial continuation in order to guide a first partial flow or a second partial flow, respectively, of the cooling fluid, the first partial flow and the second partial flow preferably having a first fluid temperature or a second fluid temperature, respectively.

By providing at least two partial extensions, the temperature distribution within the cooling system can be influenced in an advantageous manner, which is advantageous for achieving a cooling effect that can be achieved. The partial continuation can be designed in terms of its shape and diameter such that the cooling fluid is divided as desired into a first partial flow and a second partial flow and is guided such that it comes into heat-conducting contact with the region that generates high heat in a targeted manner. The partial continuation can extend partially both parallel and transverse to the longitudinal axis of the cooling jacket.

In a further preferred embodiment, the bearing shield is constructed as an assembly comprising a first bearing shield part and a second bearing shield part, which are arranged to interact cooperatively so as to constitute the cooling channel continuation.

In contrast to the monolithic embodiment, the design of the bearing shield as an assembly having at least two bearing shield parts allows a design with a complex spatial distribution of the cooling channel extensions to be achieved without the use of costly manufacturing methods in the manufacture of the bearing shield. The cooling channel extension can be formed by machining the first and second bearing shield parts by milling out the respective portions of the cooling channel extension contour in the first and second bearing shield parts, respectively, and by fitting the two bearing shield parts together to form the cooling channel extension. The advantage with this split construction is the high degree of replaceability of the individual components during maintenance, without having to replace the entire bearing shield.

In a further preferred embodiment, the first bearing shield part or the second bearing shield part has a higher mechanical stiffness than the respective other bearing shield part. For example, one bearing shield part can be designed as a cast part, while the other bearing shield part can be designed as a sheet metal part or as a stamped part.

By configuring the first bearing shield part to have a higher mechanical strength than the second bearing shield part, a high degree of functional separation can be achieved. This is advantageous in particular when the first bearing shield part is constructed primarily for supporting the rotor and accordingly has to have a high rigidity, while the second bearing shield part has a large part of the flow-guiding structure of the cooling channel continuation or defines said cooling channel continuation. The main part of the occurring bearing forces can thus be supported directly by the first bearing shield part, while the second bearing shield part can be protected against impermissible deformations which occur as a result of structural damage to the flow guide.

In a further preferred embodiment, the higher mechanical stiffness is formed by an increased material stiffness and/or by an increased geometrical moment of inertia, preferably by providing ribs and/or beads which form the respective bearing shield part.

The higher rigidity is influenced both by the properties of the material from which the respective bearing shield is made and by its shape. In the selection of the material, the modulus of elasticity of the material to be used can be taken into account, in particular, already during the design of the structure, in order to be able to evaluate whether an additional increase in the structural rigidity is necessary or whether even a smaller wall thickness can be achieved in order to reduce the component weight. In order to adjust the rigidity structurally, the moment of inertia of the relevant cross section of the bearing shield can be adjusted in particular by standardized structural elements, such as ribs, beads, folds, etc. The standardized structural element has the advantage that it can bring about a known stiffening effect, so that no separate design of the structural reinforcing element is required during construction. Thereby reducing construction expenditures and costs associated therewith.

In a further preferred embodiment, a cooling channel continuation is provided between the bearing shield and a housing which is arranged axially on the heat conducting structure for axially enclosing the second heat source along the longitudinal axis.

In this embodiment, it is advantageous if the housing of the second heat source can be designed independently of the shape of the heat-conducting structure. This may be necessary in particular when the second heat source may have a different shape or output a different amount of heat depending on the structural shape. To eliminate this, the bearing shield can comprise a first part of the fluid channel continuation, which is formed in one piece, while another part of the same fluid channel continuation can be formed separately in the housing to be provided for enclosing the second heat source. The uniform design of the bearing shield and the unique design of the housing can thus form a unique variant of the cooling channel extension. Whereby the cooling effect can be further improved.

In a further preferred embodiment, the heat-conducting structure has a flange surface or other type of connection surface, which is designed for the detachable arrangement of the housing on the heat-conducting structure, in particular by means of a screw connection.

The advantage achieved with such a connection surface or flange surface is that the housing can be simply positioned on the heat conducting structure. This prevents errors in the assembly of the two components and reduces the error costs.

In a further preferred embodiment, the cooling channel continuation is formed by the outer side of the housing and the outer side of the bearing shield.

In this embodiment, the cooling channel continuation extends only between the mutually facing surfaces of the bearing shield and the housing for enclosing the second heat source. The cooling channel extension can thus be easily accessed for maintenance purposes and, if necessary, can be serviced and/or cleaned with little effort.

In a further preferred embodiment, the housing has a connection opening for the fluid-conducting connection of the interior region of the housing to the cooling channel continuation.

In contrast to the cooling channel continuation provided on the surface of the housing for surrounding the second heat source, the design with the connection opening offers the possibility of conducting the cooling fluid from the cooling channel continuation into the interior region of the housing. Thereby, the second heat source arranged in the housing is enabled to be in direct heat conducting contact with the cooling fluid, whereby the cooling effect can be optimized. In one possible embodiment of this embodiment, the second heat source is surrounded by a flexible or rigid line or another type of conduit through which the cooling fluid flows.

In a further preferred embodiment, the second heat source has a flow-conducting region, which is connected in a flow-conducting manner to the cooling channel.

By forming the flow guiding region in or on the second heat source itself, the cooling fluid can be guided directly through the second heat source. In one possible embodiment of this embodiment, the second heat source has an integrated fluid channel in order to desirably conduct the cooling fluid within the second heat source to the region where the greater heat is generated. This has the advantage of a more efficient and direct cooling effect.

In a further preferred embodiment, a retaining element, in particular a torque support, is arranged on the outside of the cooling sleeve facing away from the heat conducting structure.

The retaining member may be configured to position the cooling sleeve in a determined position. As long as the cooling system is designed for cooling the electric drive unit, forces and torques generated by the drive unit, in particular for driving the vehicle, can also be supported by the retaining member. As long as the heat conducting structure is a stator carrier surrounded by a cooling sleeve, it may not be necessary to form a mechanical interface for the retaining element in the structural design of the stator carrier, since the retaining element may be arranged directly on the cooling sleeve. The holding member may in particular be a torque support, which, when used with the electric drive unit, may have a high torque stiffness in order to transmit the drive torque of the electric drive unit directly and with low vibrations to the drive train of the electric vehicle.

In a further preferred embodiment, the heat conducting structure comprises a first cross-sectional area along the longitudinal axis having a first diameter, which is designed to surround the first heat source, and a second cross-sectional area along the longitudinal axis having a second diameter, which is designed to surround the second heat source. The two diameters may have different forms and/or dimensions.

The formation of two different cross-sectional areas inside the heat-conducting structure brings the advantage that only one component is required to surround both the first and the second heat source, although the first and the second heat source are usually of different dimensions. The cross-sectional transitions required for this purpose can be formed subsequently, in particular by internal high-pressure forming, on the cylindrical heat-conducting structure by means of a corresponding deformation forming. In this way, different geometries for the heat-conducting structure can be produced economically starting from a heat-conducting structure which has uniform characteristics at the beginning.

In a further preferred embodiment, the retaining member is arranged in the region of the bearing shield along the longitudinal axis.

The arrangement of the retaining member in the region of the bearing shield brings about the advantage that the bearing forces generated can be transmitted via the bearing shield to the retaining member along a direct force transmission path. Thereby, the deformability of the cooling system can be purposefully limited.

In a further preferred embodiment, the cooling sleeve has at least one inlet region, which is designed for introducing the cooling fluid into the cooling channel, and at least one outlet region, which is designed for discharging the cooling fluid out of the cooling channel.

The separation of the inlet and outlet regions gives rise to the advantage that the incoming cooling fluid is at a lower temperature than the outgoing cooling fluid and that the incoming cooling flow is not heated by the outgoing cooling fluid. Thereby increasing the achievable efficiency of the cooling system.

In a further preferred embodiment, the cooling system has a heat exchanger which is designed to bring the cooling fluid from a first temperature to a second temperature, wherein the first temperature substantially corresponds to the discharge temperature of the cooling fluid in the outlet region and the second temperature substantially corresponds to the inlet temperature of the cooling fluid in the inlet region.

By configuring the heat exchanger as a component of the cooling system, the heat exchanger can be operated with power regulation, in which the cooling power provided by the heat exchanger is regulated as a function of the temperature of the cooling fluid tapped off in the outlet region. For this purpose, the heat exchanger has a regulating system which is connected to a temperature sensor. The temperature sensor may be configured to detect a derived temperature and send the derived temperature to a conditioning system. If the derived temperature exceeds a predefined limit value, the control system can conclude therefrom that the cooling power provided by the heat exchanger is insufficient to derive a heat flow of the first heat source and the second heat source. Based on this, the cooling power is adjusted in a PID control or the like. If the derived temperature is, on the other hand, below the same or another limit value, the efficiency of the system can be increased by adjusting the heat exchanger to a lower cooling capacity.

In a further preferred embodiment, the inlet region is arranged axially along the longitudinal axis at a distance from the second heat source which is smaller than the distance from the outlet region.

If the cooling fluid passes through the region in which the first and second heat sources are arranged along the longitudinal axis, the cooling fluid is first heated by one of the two heat sources and subsequently by the respective other heat source. In the motor, the stator is preferably the first heat source and the power electronics the second heat source, the heat transferred need not have the same value. In particular, owing to the design of the stator and the contact area with the stator carrier, a greater amount of heat can be dissipated by the stator than by the power electronics. This leads to a reduced cooling effect of the cooling fluid in the area of the power electronics if the cooling fluid is thus overheated by the stator. To eliminate this problem, the inlet region can be arranged in the region of the second heat source, in particular in the region of the power electronics, so that the cooling fluid first flows through the region of the second heat source before it reaches the first heat source and from there the outlet region.

In a further preferred embodiment, the cooling system has a cooling circuit comprising a cooling fluid for absorbing and discharging a total heat input, a fluid storage container for storing the cooling fluid, and a line system which is designed to introduce the cooling fluid into the cooling channel in an inlet region and to discharge the cooling fluid from the cooling channel in an outlet region

The cooling circuit, which is designed to circulate the cooling fluid between the fluid storage container and the cooling channel, has the advantage that the cooling fluid present in the cooling system can be used over the entire service life of the cooling system. Thus, the cooling cycle only needs to be filled once with cooling fluid, whereby the additional cost for refilling the cooling fluid can be eliminated. Preferably, the cooling system is designed with a sealing element which ensures that the cooling fluid has only a negligibly small leakage amount, so that no refilling of the cooling fluid is required. Thereby, the maintenance cost of the cooling system is low. In particular, when the cooling system is used in an electric vehicle, its components can be designed such that special requirements with regard to their accessibility do not have to be taken into account.

In a further preferred embodiment, the cooling system has a pump unit which is designed for conveying the cooling fluid from a fluid storage container into the cooling channel and/or for conveying the cooling fluid from the cooling channel into a fluid storage container.

In accordance with the advantages of the heat exchanger as a component of the cooling system, the provision of the pump unit allows the volumetric flow and/or the mass flow of the cooling fluid entering the cooling channel to be adjusted as desired. This can be advantageous, in particular, in conjunction with a regulating system, since the pump unit can also be regulated at least partially as a function of the discharge temperature. Whereby the cooling effect can be achieved efficiently.

Drawings

Further advantages and embodiments of the invention result from the following description of an exemplary embodiment with reference to the drawings.

FIGS. 1-15 respectively illustrate embodiments of a cooling system;

and

fig. 16 shows an electric vehicle with an electric drive unit and a cooling system.

Detailed Description

Fig. 1 shows a cooling system 1, which comprises a cooling sleeve 2, which extends along a longitudinal axis 3 and surrounds a sleeve-like stator carrier 4 of an electric machine M.

The cooling sleeve 2 has a substantially cylindrical basic shape and has a wall which is corrugated along a longitudinal axis. In the exemplary embodiment shown, such a wave form is configured such that it has a slope (not labeled) along the longitudinal axis 3, thereby forming a thread-like space which is delimited on one side by the cooling sleeve 2. Alternatively to the spiral-shaped formation of the space, other distributions may also be used in which the space extends at least partially along or parallel to the longitudinal axis of the cooling jacket. On the other hand, the cooling sleeve is connected to the stator support 4 and is mechanically fixed to the stator support, preferably by a shrink fit. The connection is formed in particular by respective contact regions which are associated with the wave shape of the wall of the cooling sleeve. In these regions of smaller diameter, the cooling sleeve 2 is formed plastically and elastically on the outside of the stator carrier 4, whereby a surrounding cooling channel 5 is formed. Additionally or alternatively, the connection can be formed by a material bond, in particular by soldering.

The cooling channel 5 has an inlet E through which a cooling fluid 6 enters the cooling channel, which cooling fluid is re-flown out of the cooling channel through an outlet (not visible). It is within the scope of the invention that the inlet E may also serve as an outlet and vice versa.

The stator 7 is arranged on the inner side 4i of the stator carrier 4 and is connected to the stator carrier 4 in a thermally conductive manner. The stator carrier 4 thus forms a heat conducting structure. The stator 7 generates heat during operation of the electric machine M due to known effects, which heat is transferred by the stator via a heat-conducting connection in the form of a hot flow

Is transferred to the stator support 4.

The power electronics 8 are arranged axially offset from the stator 7 along the longitudinal axis 3. The power electronics 8 are likewise in heat-conducting connection with the stator carrier 4, as are the stators 7. During operation of the electric machine, the power electronics also generate heat, which is converted into a heat flow by the power electronics via a thermally conductive connection

Is transferred to the stator support 4.

The stator 7 thus constitutes the first heat source, while the power electronics 8 constitute the second heat source. Total heat flow

By heat flow

And

the first and second heat flows may have different proportionality relationships to each other. Cooling system for an electric machine designed for heat flow

And

is independently derived from the total heat flow

In that a cooling fluid 6 is caused to flow around the stator support 4 in a region along the longitudinal axis 3, in which region both the stator 7 and the power electronics 8 are arranged in order to absorb and dissipate heat.

The cooling channel 5 has a cooling channel geometry 9 which substantially corresponds to the geometry of the cooling sleeve 2. In the region of the smaller cross section, that is to say in the region of the wave troughs thereof, the cooling sleeve 2 is in contact with the stator carrier 4 and has a joining region 10 at the contact point, in which the cooling sleeve is connected to the stator carrier 4 in a material-locking manner. The connection is designed as a material-locking soldered connection, but within the scope of the invention it is also possible to realize it non-positively by means of a crimped connection and by a combination of material-locking and non-positive joining methods. By means of said connection, the adjacent passages of the cooling channel 5 are separated from each other hermetically or fluid-tightly, whereby mixing of the cooling fluid 6 between the passages (so-called "cross-talk") is avoided and an optimal temperature distribution in the cooling system can be achieved.

The stator 7 is substantially sleeve-shaped and encloses a rotor 13 which is rotatably mounted in its interior. The rotor 13 is supported by a bearing shield 11 provided on the a side of the motor via a first roller bearing L1 and by a bearing shield 12 provided on the B side of the motor via a second roller bearing L2. In addition to its bearing function, the first bearing shield 11 also serves to form part of a housing which encloses the transmission components (not shown) mechanically connected to the rotor 13.

The second bearing shield 12 is arranged axially along the longitudinal axis 3 between the stator 7 and the power electronics 8 and is pressed into the stator carrier 4, whereby the second bearing shield is mechanically and thermally conductively connected to the stator carrier. The cover D closes the inner region of the stator bearing 4 at the end.

Fig. 2 shows a second exemplary embodiment of a cooling system 1 which has, in addition to the components shown in fig. 1, a first axial through opening 14 and a second axial through opening 15 in a bearing shield 12.

The first axial through hole 14 is configured for electrically conductively connecting the stator 7 and the power electronics 8. In the case of an electric machine to be cooled, the through-holes 14 can thus be used to apply the alternating voltage converted by the power electronics 8 to the electrical conductors of the stator 7. The axial through-hole 14 may be designed to be sealed in order to separate the power electronics 7 from the lubricant used in the process of supporting the stator 7.

The second axial through hole 15 is designed for connecting the power electronics 8 to the rotor 13 via a converter, not shown here, in order to enable, in particular, a rotational speed regulation for the electric machine. The second axial through-hole 15 can also be designed to be sealed.

Fig. 3 shows a third exemplary embodiment of a cooling system 1, in which the stator carrier 4 has a partially different cross section in some regions. The stator 7 and the power electronics 8 have different dimensions in the radial direction with respect to the longitudinal axis 3. Correspondingly, the stator carrier 4 has a first cross-sectional area 35 and a second cross-sectional area 36, the stator 7 being arranged in the first cross-sectional area 35 and the power electronics 8 being arranged in the second cross-sectional area 36.

Between the cross-sectional area 35 and the cross-sectional area 36, the stator carrier 4 has a cross-sectional transition K, in which the stator carrier 4 is conically formed. This conically configured transition region serves on the inner side 4i of the stator carrier 4 for supporting the bearing shield 12 in the axial direction along the longitudinal axis 3 relative to the longitudinal axis 3. This is advantageous because the bearing shield 12 can transmit axial forces to the stator carrier 4 in a form-fitting manner, whereby in particular the crimp connection between the bearing shield 12 and the stator carrier 4 can be designed to be small in size. Furthermore, the mounting of the bearing shield 12 in the stator bearing 4 is simplified, so that it can be positioned on a mechanical stop in the form of a conically configured inner side 4i of the stator bearing 4.

The cooling jacket 2 is formed or arranged along the longitudinal axis 3 only in the first cross-sectional region 35. In accordance with the advantages obtained in the installation of the bearing shield 12 in the cross-sectional transition K, it is also possible to use the extension in the cross-sectional profile of the stator carrier 4 as a bearing surface for the installation of the cooling jacket 2. Heat flow from power electronics 8

Is transferred via the stator carrier 4, which acts as a heat conducting structure.

Furthermore, the stator carrier 4 has a flange surface 28, on which the stator carrier 4 is sealed or fluid-tight with a cover D. This reduces the assembly effort.

Fig. 4 shows a fourth embodiment of the cooling system 1. According to fig. 4, the cooling jacket 2 extends both in the first cross-sectional area 35 and in the second cross-sectional area 36. Thereby, the cooling effect is increased compared to the third embodiment according to fig. 3, in particular in the second cross-sectional area 36 where the power electronics 8 are arranged.

Furthermore, a retaining member 34, which is designed as a torque support, is provided on the outside 37 of the cooling sleeve at the level of the bearing shield 12. Thereby, forces acting between the rotor 13 and the bearing shield 12 can be directly supported, thereby avoiding force deflections and overall reducing cooling system deformations. The holding member 34 has a through-opening 34d, by means of which the electric motor can be detachably fixed on the vehicle, in particular by means of a screw connection.

Fig. 5 shows a fifth exemplary embodiment of the cooling system 1, which includes a bearing shield 12, which is designed as a bent, deep-drawn sheet metal part. Similar to fig. 2 and 3, the bearing shield 13 is shown to include a first axial through bore 14 and a second axial through bore 15. Configuring bearing shield 12 as a deformed sheet metal part achieves a lower component weight while having a higher achievable shape stability.

Fig. 6 shows a sixth exemplary embodiment of the cooling system 1, in which the stator carrier 4 has radial through openings 18. In the embodiment shown, said radial through holes 18 are formed only through the wall of the stator support 3; however, it is also within the scope of the invention for the radial through-opening to be provided in the end-side edge region of the stator carrier 4, so that the through-opening is only closed in a circumferential manner when it is used in conjunction with a further housing element (not shown).

Furthermore, the bearing shield 12 is designed as an assembly having a first bearing shield part 23 and a second bearing shield part 24. These first bearing shield part 23 and second bearing shield part 24 engage in a sealing manner in the region of the bearing seat of the bearing L2 and are partially spaced apart from one another, so that a cooling channel continuation 19 is formed between the two bearing shield parts, said cooling channel continuation being connected in a fluid-conducting manner to the radial through opening 18.

The first bearing shield part 23 and the second bearing shield part 24 can be designed as deep-drawn sheet metal parts and/or solid castings, which can be joined to one another detachably, in a material-locking manner or by means of deformation molding.

Fig. 7 shows a seventh embodiment of the cooling system 1, in which the bearing shield 12 has a first bearing shield part 23 and a second bearing shield part 24 which, analogously to the embodiment according to fig. 6, are configured to cooperate in order to form a cooling channel continuation. Unlike the sixth embodiment, the second bearing shield part 24 has a higher mechanical stiffness than the first bearing shield part 23. This is preferably achieved in that the second bearing shield part 24 is designed as a cast part with a larger wall thickness in certain regions than the first bearing shield part 23, which is designed as a sheet metal part. Thus, the second bearing shield component 24 may be sized such that it receives a greater portion of the force supporting the rotor 13 than the first bearing shield component 23.

Furthermore, as shown in fig. 7, the cover D has an opening in the form of a neck opening 25, through which the power electronics 8 can be connected to a not shown power supply system, in particular a battery, via electrical conductors 26.

Fig. 8 shows an eighth exemplary embodiment of the cooling system 1, in which the stator carrier 4 has a radial through-opening 18, to which a cooling channel continuation 19 is fluidically connected. In contrast to fig. 1 to 7, the stator carrier 4 extends along the longitudinal axis 3 substantially only over the region in which the stator 7 is also arranged. A housing 27, which is formed separately from the stator holder, is provided on the front end side of the stator holder 4 and surrounds the power electronics 8.

The cooling channel continuation 19 is formed by an outer side 29 of the housing 27 and an outer side 30 of the bearing shield. The power electronics 8 achieve cooling by direct heat-conducting connection of the power electronics to the inside of the housing 27. The housing thus forms part of the heat conducting structure. In order to maximize the cooling effect, the inner part of the housing 27 is configured partially corresponding to the geometry of the power electronics 8. In this region, the inside of the housing 27 is in direct thermally conductive contact with the power electronics 8. By the same geometry the contact area between the housing 27 and the power electronics 8 is increased.

Fig. 9 shows a ninth embodiment of the cooling system 1, in which the housing 27 surrounds the power electronics 8 such that an intermediate space 32 is formed between the wall of the housing 27 and the power electronics 8. In order to achieve a heat transfer via the intermediate space 32 without having to make direct contact between the power electronics 8 and the housing 27, the housing 27 has a connection opening 31, via which the interior of the power electronics 8 or the housing 27 is connected in a fluid-conducting manner to the cooling channel continuation 19.

Fig. 10 shows a tenth exemplary embodiment of a cooling system 1, which has an inlet E and an outlet a for a cooling medium or cooling fluid and in which the inlet E is arranged directly in the region of the power electronics 8 along the longitudinal axis 3. It is thereby possible to achieve that the cooling fluid 6 is not subjected to the heat flow of the stator 7 when it flows to the power electronics 8 to be cooled

Heating in advance.

Fig. 11 shows an eleventh exemplary embodiment of a cooling system 1, in which the power electronics 8 have a flow-conducting region 33, which flow-conducting region 33 is connected in a flow-conducting manner to the inlet E arranged on the end side and to the cooling channel 5. Similar to the design according to the tenth embodiment of fig. 10, an improved cooling effect on the power electronics 8 can be achieved by using a direct flushing of the (fresh) cooling fluid 6 to the power electronics 8, since the cooling fluid 6 is not preheated by other heat sources.

Fig. 12 shows a twelfth exemplary embodiment of a cooling system, in which the bearing shield 12 has a cooling channel continuation 19 which is formed integrally in the bearing shield or is formed integrally with the bearing shield 12. The bearing shield 12 can be produced in one piece by a production method of the prototype, whereby the assembly work and the costs associated therewith can be reduced. Furthermore, complex channel geometries can be produced thereby.

Furthermore, the bearing shield 12 has a mechanical interface S1, by means of which the housing 27 surrounding the power electronics 8 can be fastened to the bearing shield 12 by means of a screw connection. Furthermore, the power electronics 8 can be arranged on the support plate 17, which can likewise be arranged on the bearing shield 12 by means of screws via the mechanical second connection S2. The thermally conductive paste 16 is used to establish a thermally conductive contact between the power electronics 8 or the bearing plate 17 and the bearing shield 12. Thereby, a functional separation between the mechanical and thermal connection of the heat source with any heat-conducting medium can be achieved.

Fig. 13 shows a thirteenth embodiment of the cooling system 1, in which the cooling channel continuation 19 comprises a first extension 20 and a second extension 21. The connection of the power electronics 8 is similar to the embodiment according to fig. 11, by means of a screw connection and a thermal paste 16. In the exemplary embodiment according to fig. 13, the first partial extension 20 and the second extension 21 are connected to one another in a fluid-conducting manner, the fluid-conducting connection being formed asymmetrically with respect to the longitudinal axis 3 according to fig. 14.

Fig. 15 shows an embodiment of the cooling system 1, in which the radial through-holes 18 of the stator carrier 4 form a flow-conducting connection between the cooling channel 5 and the power electronics 8.

Fig. 16 shows an electric vehicle F, which has an electric machine M (in particular for driving purposes) with a cooling system 1. The cooling system 1 comprises a cooling sleeve 2, which is oriented along a longitudinal axis 3. The electrical machine M comprises a stator 7 and power electronics 8 arranged along the longitudinal axis 3. The stator support 4 is arranged between said components of the electrical machine M and the cooling sleeve 2 and forms, in cooperation with the cooling sleeve 2, a cooling channel 5. The cooling medium (cooling fluid) 6 is conveyed by the electric pump P from the tank T into the heat exchanger WT, where the cooling fluid 6 is brought to a suitable nominal temperature in order to dissipate the heat generated by the stator 7 and the power electronics 8.

Claims

1. Cooling system (1), in particular for a drive motor (M) in an electric vehicle (F), the cooling system (1) having a cooling sleeve (2) with a longitudinal axis (3) and a heat conducting structure (4), the cooling sleeve (2) enclosing the heat conducting structure (4) in a region along the longitudinal axis (3), whereby a cooling channel (5) is formed between the cooling sleeve (2) and the heat conducting structure (4) for guiding a cooling fluid (6) in the cooling channel (5), the heat conducting structure (4) being configured and defined for accommodating a first heat source (7), in particular a stator of the drive motor (M), in the region for the electric vehicle (F),

it is characterized in that the preparation method is characterized in that,

the heat conducting structure (4) is designed for thermally conducting contact with a second heat source (8), in particular power electronics in an electric vehicle (F) for driving an electric motor (M), the second heat source (8) being arranged axially opposite the first heat source (7) along the longitudinal axis (3).

2. A cooling system (1) according to claim 1, characterized in that the heat conducting structure (4) is at least partly constructed and defined for accommodating a second heat source (8).

3. Cooling system (1) according to one of the preceding claims, characterized in that the heat conducting structure (4) comprises a stator support for a drive motor (M), in particular a sleeve-shaped stator support.

4. Cooling system (1) according to one of the preceding claims, characterized in that the cooling sleeve (2) is at least partially constructed corrugated, the cooling sleeve (2) is preferably made of a metallic material, and the cooling channel (5) has at least partially a cooling channel geometry (9) corresponding to the corrugated geometry of the cooling sleeve (2).

5. The cooling system (1) according to one of the preceding claims, characterized in that the cooling channel (5) is at least partially configured in a helical or threaded manner along the longitudinal axis (3) and/or about the longitudinal axis (3).

6. Cooling system (1) according to one of the preceding claims, characterized in that the cooling sleeve (2) is connected with material-locking with the heat conducting structure (4), in particular to seal the cooling channel (5) in at least one connection region (10).

7. Cooling system (1) according to one of the preceding claims, characterized in that the heat conducting structure (4) comprises a bearing shield (12), in particular a bearing shield (12) for a drive motor (M) in an electric vehicle (F), the bearing shield (12) being arranged between the first heat source (7) and the second heat source (8) on the longitudinal axis (3).

8. Cooling system (1) according to claim 7, characterized in that the bearing shield has at least one axial through hole (14, 15) which is arranged and configured for contacting the first and/or the second heat source, in particular for electrically contacting the first and/or the second heat source.

9. Cooling system (1) according to claim 7 or 8, characterized in that the bearing shield (12) is at least partially constructed by means of shaping, in particular by deep-drawing and/or by means of prototyping, in particular by casting or by generative manufacturing.

10. The cooling system (1) according to any one of claims 7 to 9, characterized in that the bearing shield (12) is configured for thermally conductive contact with the second heat source (8) in such a way that the bearing shield (12) is configured to at least partially correspond to the geometry of the second heat source (8).

11. Cooling system (1) according to one of the claims 7 to 10, characterized in that the second heat source (8) is connected with the bearing shield by a thermally conductive intermediate layer (16), in particular the second heat source (8) is connected with the bearing shield by a thermally conductive paste.

12. Cooling system (1) according to one of the claims 7 to 11, characterized in that the second heat source is arranged on a support plate (17), which support plate (17) is mechanically connected, in particular detachably connected, to the bearing shield (12), preferably by means of bolts to the bearing shield (12), most preferably the second heat source is arranged on the side of the bearing shield (12) facing away from the first heat source (7).

13. Cooling system (1) according to one of the preceding claims, characterized in that the heat conducting structure (4) has a radial through hole (18), the cooling channel (5) being in flow-guiding connection with the radial through hole (18).

14. The cooling system (1) according to any of claims 7 to 12, characterized in that the bearing shield (12) comprises a flow-conducting cooling channel continuation (19), which cooling channel continuation (19) is directly or indirectly flow-conducting connected with the cooling channel (5).

15. Cooling system (1) according to claim 14, characterized in that the cooling channel continuation (19) is integrally formed inside the bearing shield.

16. Cooling system (1) according to claim 14 or 15, characterized in that the cooling channel continuation (19) comprises a first part-continuation (20) and a second part-extension (21) in order to lead a first partial flow or a second partial flow, respectively, of cooling fluid, the first partial flow and the second partial flow preferably having a first fluid temperature or a second fluid temperature, respectively.

17. Cooling system (1) according to any one of claims 14 to 16, characterized in that the bearing shield (12) is designed as an assembly comprising a first bearing shield part (23) and a second bearing shield part (24), the first bearing shield part (23) and the second bearing shield part (24) being arranged to cooperate with each other to constitute the cooling channel continuation (19).

18. The cooling system (1) according to claim 17, characterized in that the first bearing shield part (23) or the second bearing shield part (24) has a higher mechanical stiffness than the respective other bearing shield part.

19. Cooling system (1) according to claim 18, characterized in that the higher mechanical stiffness is formed by an increased material stiffness of the respective bearing shield part (23, 24) and/or by an increased geometrical moment of inertia, preferably by ribs and/or beads.

20. The cooling system (1) according to any one of claims 14 to 19, characterized in that the cooling channel continuation (19) is provided between the bearing shield (12) and a housing (27) which is provided axially on the heat conducting structure (4) for axially enclosing the second heat source (8) along a longitudinal axis (3).

21. Cooling system (1) according to claim 20, characterized in that the heat conducting structure (4) has a flange face (29) configured for the detachable arrangement of the housing (27) on the heat conducting structure (4), in particular the housing (27) is detachably arranged on the heat conducting structure (4) by means of a screw connection.

22. Cooling system (1) according to claim 20 or 21, characterized in that the cooling channel continuation (19) is constituted by an outer side (29) of the housing and an outer side (30) of the bearing shield.

23. Cooling system (1) according to claim 22, characterized in that the housing (27) has a connection opening (31) for the fluid-conducting connection of an inner region of the housing (27) to the cooling channel continuation (19).

24. Cooling system (1) according to one of the preceding claims, characterized in that the second heat source (8) has a flow guiding area (33), which flow guiding area (33) is flow-conductively connected with the cooling channel (5).

25. Cooling system (1) according to one of the preceding claims, characterized in that a retaining member (34) is provided on an outer side (37) of the cooling sleeve facing away from the heat conducting structure (4), the retaining member (34) being in particular a torque support.

26. The cooling system (1) according to any one of the preceding claims, wherein the heat conducting structure (4) comprises a first cross-sectional area (35) having a first diameter and a second cross-sectional area (36) having a second diameter along the longitudinal axis (3), the first diameter being configured for enclosing the first heat source (7) and the second diameter being configured for enclosing the second heat source (8).

27. Cooling system (1) according to at least claims 8 and 25, characterized in that the retaining member is arranged in the region of the bearing shield (12) along the longitudinal axis (3).

28. The cooling system (1) according to any one of the preceding claims, characterized in that the cooling sleeve has at least one inlet area (E) configured for introducing the cooling fluid (6) into the cooling channel (5) and at least one outlet area (A) configured for leading the cooling fluid (6) out of the cooling channel (5).

29. A cooling system (1) according to claim 28, characterized in that the cooling system has a heat exchanger (WT) configured to temper the cooling fluid (6) from a first temperature, which substantially corresponds to a lead-out temperature of the cooling fluid in the outlet area (a), to a second temperature, which substantially corresponds to an inlet temperature in the inlet area (E).

30. Cooling system (1) according to claim 28, characterized in that the inlet area is arranged axially along the longitudinal axis (3) at a distance from the second heat source (8) which is smaller than the distance from the outlet area (a).

31. The cooling system (1) according to claim 28, characterized in that it has a cooling cycle (K) comprising a cooling fluid (6) for absorbing and discharging a total heat input, a fluid storage container (T) for storing the cooling fluid (6), and a duct system configured to introduce cooling fluid into a cooling channel in an inlet region (E) and to discharge cooling fluid from the cooling channel (5) in an outlet region (a).

32. Cooling system (1) according to at least claim 31, characterized in that it has a pump unit (P) configured for conveying the cooling fluid (6) from the fluid storage container (T) to the cooling channel and/or for conveying the cooling fluid from the cooling channel into the fluid storage container.

33. Electric drive unit, in particular for an electric vehicle (F), having an electric machine (M) comprising a rotor (13), a stator (7), a stator support (4) and a cooling system (1) according to one of the preceding claims, wherein the stator support (4) is configured as the heat conducting structure.

34. An electric vehicle having an electric drive unit according to claim 33.

35. Method for cooling an electric drive unit, comprising the steps of:

a) providing a cooling system (1) according to any one of claims 1 to 32;

b) tempering the cooling fluid (6) to an inlet temperature;

c) feeding a cooling fluid (6) into the cooling channel (5);

d) transferring heat from the first heat source (7) and the second heat source (8) to the heat conducting structure (4);

e) transferring heat from the heat conducting structure (4) to the cooling fluid (6);

f) conveying the cooling fluid (6) out of the cooling channel (5).