Air-cooled e-axle

Abstract

Air-cooled e-axle (1) for an electric vehicle drive, with an electric motor which is in thermal coupling with a heat exchanger (3) designed for air cooling, wherein an underbody panel (4) is provided which has a passage opening (5) for an air supply to the heat exchanger (3).

Description

The invention relates to an air-cooled E-axle (electric axle, electric axle) for an electric motor vehicle drive, having an electric motor (electric motor) which is in thermal coupling during operation with a heat exchanger designed for air cooling. An electric drive system / electric drive system thus constructed is composed of an electric motor as a drive source and a reduction gear. The system has oil lubrication. The oil supply can be realized passively or by a pump. In both cases, the oil is conveyed from a common oil pan via a suitable supply in the housing to the electric motor and to the transmission. In the example shown, the electric motor has a stator cooling system. Via a central inlet, the oil reaches the stator windings directly and subsequently into the interior of the electric motor. In addition, the electric motor can also have a rotor cooling system. Additional oil reaches the rotor package via the rotor shaft and subsequently also into the interior of the electric motor. Both the electric motor and the transmission have a corresponding oil guide in order to guide the oil back into the oil sump again. Ribs are provided at the lower part of the E-axis to provide an additional cooling effect.In motor vehicles, components of the drive train, such as the traction motor, i.e. the motor for providing the drive power for overcoming the driving resistances, or a traction transmission, i.e. a transmission for adapting the drive power provided by the traction motor to the driving resistances, are lubricated and cooled. In this case, it is a general aim to provide this lubricating / cooling functionality with the simplest possible means, but also with great efficiency.In order to ensure permanent operation of e-axles / electric-axle systems (e-axle systems), the waste heat arising from losses must be dissipated as efficiently as possible. For this purpose, oil is used in most cases in order to remove the heat generated directly from the source. Sources that may be used include, for example, the stator and rotor of the electric drive motor (electric drive motor), but also bearings and toothings in the transmission. The oil primarily dissipates the heat from the source and distributes it in the E-axis system. The waste heat is ultimately transported away from the drive by heat exchange with the water cooling circuit of the motor vehicle or directly to the ambient air. According to the prior art, the components required for this heat exchange are currently designed as independent components and are accordingly integrated into the cooling circuit. For this purpose, oil-water heat exchangers, water jackets, oil-air heat exchangers or ribbings on the housing are used. The water circuit of the e-vehicle further includes a further air-water heat exchanger (usually arranged in the front part of the e-vehicle) in order to dissipate the heat to the ambient air.Furthermore, in some cases it may also be necessary to remove the waste heat from the drive directly to the environment. This can be the case when the drive is placed on the rear axle, for example. However, there is no connection to the e-vehicle cooling circuit there. It would likewise be the case if the drive power is so low that the ambient circulation can also remove the waste heat directly without problems.Furthermore, in these cases, ribbings or oil-air heat exchangers can be provided on the lower part of an E-axis. According to the prior art, the arrangement of an air heat exchanger on the underside of the electric drive can advantageously be combined with the underbody cladding of an electric motor vehicle. In the case of an air-cooled system, the power electronics of the electric drive will in most cases be incorporated into the cooling or air-conditioning circuit of the e-vehicle.According to the prior art, claddings on the underbody are often used in e-vehicles / e-motor vehicles. These claddings serve to protect the drive and battery systems, but also to efficiently guide the flow of the air flowing through.In the field of the technical invention, cooling concepts exist for the e-drive train of an electrically operated motor vehicle (e-motor vehicle). The cooling concepts are distinguished in particular in that they use the ambient air as a cooling medium. For this purpose, for example, special designs of heat exchangers or ribbings on housings of heat-conducting components of the electric drive train are used.The publication DE 20 2012 007 775 U1 discloses a utility model for a heat exchanger with adapter module. The main claim is directed to a heat exchanger module comprising: a heat exchanger comprising a plurality of stamped heat exchanger plates arranged in stacked relationship and sealed by brazing, the heat exchanger having a base surface corresponding to the surface defined by the stack of heat exchanger plates; a plurality of first fluid paths and a plurality of second fluid paths arranged between adjacent heat exchanger plates in alternating spaced relationship; a pair of first fluid branches extending through the heat exchanger and interconnected by the first fluid paths, the pair of first fluid branches having an inlet branch and an outlet branch; a pair of second fluid branches extending through the heat exchanger and interconnected by the second fluid paths, the pair of second fluid branches having an inlet branch and an outlet branch; an adapter module mounted on an end of the heat exchanger, the adapter module having: at least one fluid transfer passage formed in the adapter module for communicating with one of the inlet and outlet branches of one of the pairs of fluid branches; a first opening communicating with the at least one fluid transfer passage, the first opening being located outside of the heat exchanger base; and a second opening for communicating with the other of the inlet and outlet branches of the pair of fluid branches; wherein the first and second fluid openings have mounting surfaces oriented and configured for direct communication with corresponding fluid openings in a housing of an automobile system component.The document EP 3 521 090 A1 discloses a motor vehicle cooling device. The cooling device for an automobile includes a heat exchange type radiator body and an air intake passage disposed in the rear part of the automobile. The air intake passage extends rearward from the radiator body in the longitudinal direction of the motor vehicle and is arranged such that the air intake passage is slidable forward in the motor vehicle relative to the radiator body upon application of an impact load to the air intake passage. The radiator body is attached to a body of the motor vehicle, while the air intake duct is attached to the radiator body such that a fastening strength of the air intake duct to the radiator body is less than a fastening strength of the radiator body to the body of the motor vehicle. The oil from the drive is pumped by a pump through an external heat exchanger, which removes the heat to the environment. This is an air-cooled drive unit.The document WO 2022 / 222 909 A1 relates to a cooling system for an integrated drive train assembly and an integrated power electronics assembly of an electric motor vehicle. The integrated electric powertrain (electric powertrain) assembly includes an electric motor, a reduction gear mechanically coupled to the electric motor, and an inverter electrically connected to the electric motor and the integrated power electronics assembly. The cooling system includes a cooling circuit configured to be flowed through by a liquid coolant and distribute the liquid coolant in the integrated e-powertrain assembly and the integrated power electronics assembly to cool all components in the two assemblies. The disclosure also relates to an electric motor vehicle comprising a cooling system according to the above description. The power electronics and also the inverter are cooled directly by air.The document DE 10 2016 211 226 B3 discloses an actively lubricated drive concept in which the waste heat from the interior of the drive is transferred through an oil-water heat exchanger to a water circuit. According to the prior art, comparable oil-water heat exchangers are currently designed as a stand-alone component and are accordingly integrated into the cooling circuit.US 2021 / 0 221 253 A1 shows a battery-electric vehicle with air cooling.US 2013 / 0 059 519 A1 discloses an air supply device for introducing air into the vehicle and at the same time preventing undesired foreign substances from entering the vehicle.The prior art further includes air cooled E-axles, which are however partitioned off by the under-floor guard.The present invention has for its object to achieve an increase in efficiency and improvement in efficiency of E-axis / E-axis systems compared to the prior art. Known disadvantages are to be eliminated or at least reduced.In an E-axle presented at the beginning, this is achieved according to the invention in that an underbody cladding is present, which has a through-opening for an air supply of the heat exchanger. The cladding according to the invention now enables efficient use of the ambient air for direct cooling of the electric drive by the ambient air.In other words, the invention relates to an air duct integrated into the E-axle / an E-axle system, which connects the advantages of an underbody cladding to efficient cooling of the drive. The integrated air duct is designed as an air supply device which is integrated directly into the underbody of the E-axle. A cutout in the underbody protection permits efficient use of the heat exchanger. The air cooling direction takes over the function of an additional cover of the heat exchanger with integrated flow guidance and at the same time the function of an underbody protection. Furthermore, the air supply device comprises a ventilation grille which can be integrated into the underbody protection and is designed for supplying relative wind for cooling or for removing heat by passing through air, known as "air flushing". By means of the integrated air guidance, different cooling concepts for an e-drive train of an electrically operated motor vehicle (e-motor vehicle) can be realized.Advantageous embodiments are claimed in the dependent claims and are explained in more detail below.In the explanation of the embodiments, the direction in which the E axis and the E motor have their longitudinal direction is defined as the longitudinal direction. This corresponds to the direction of travel of the vehicle. The transverse direction is defined orthogonally to the longitudinal direction and thus in the width direction / axial direction of the electric motor. The height direction is defined in the radial direction of the electric motor.It has proven advantageous if the through opening is configured either for passing air between an upper side of the underbody cladding on the engine side and an underside of the underbody cladding facing away from the engine side or for receiving the heat exchanger when it projects through the underbody cladding from the upper side thereof to the underside thereof.Through the through-opening, it is possible in a technically advantageous manner to guide a flow of the air in a defined manner to the components of the E-axis or the surfaces thereof acting as heat sources. These components / surfaces are preferably the heat exchanger of the E-axis and in particular its base plate, from which / the waste heat is transferred and removed in a technically advantageous manner by convective heat transfer to the air flowing past. The transferred heat flux density is technically advantageous in a positive correlation depending on the flow speed, which is preferably depending on the travel speed of the electric motor vehicle. With a higher travel speed, the flow speed preferably increases and via this the heat flux density removed under otherwise constant conditions.By arranging the through-opening in a region between the upper side of the underbody cladding on the engine side and an underside of the underbody cladding facing away from the engine, it is possible to achieve a technically more advantageous passage of the air / ambient air flowing under the underbody cladding as a result of the movement of the engine motor vehicle into the engine motor vehicle / the region on the engine side above the underbody cladding. As a result, the flow air can advantageously be used for cooling the / heat dissipation from the heat exchanger of the E-axis.Different cooling concepts can be advantageously realized by utilizing different cooling principles for heat dissipation through this embodiment of the through-opening in combination with other structural features, such as the fins / fins of air supply devices explained in the further course of the description.By configuring the through-opening for receiving the heat exchanger when it projects through the underbody cladding from its upper side to its lower side, it is technically advantageously possible to position the heat exchanger such that it / its base plate is configured for contact with the air flow. The E-axle underbody / E-axle housing exterior, more specifically the E-axle heat exchanger exterior (the side / underside facing away from the E-engine), is preferably directly accessible to ambient airflows, i.e., airflow below the underbody trim / environment. As a result, by projecting the heat exchanger / the outer side of the heat exchanger into the air flow of the underbody environment, a preferably direct convective transfer of the heat from the surface of the outer side of the heat exchanger to the ambient air flowing around the latter can be achieved.In addition, it is advantageous if an air supply device is fitted in the through-opening in order to supply air to the heat exchanger, for example actively or passively, during operation.By means of this air supply device, it is technically advantageous to guide or direct the air flow in a defined manner and to conduct the air flow approximately actively to the heat exchanger. The air supply device preferably comprises at least one predetermined air inlet and at least one predetermined air outlet for the flowing air, in order to realize an air flow and, via this, a heat dissipation in a technically advantageous manner. The air supply is realized via an air inlet provided on the air supply device and the air discharge is realized via a provided air outlet.By means of a structural design of the air supply device, which design is preferably predetermined from the flow-mechanical and thermodynamic points of view and is adapted to the E-axis of the respective E-motor vehicle and in particular to the heat exchanger, the guidance of the air flow and preferably the flow type can be / can be influenced in a technically advantageous manner with regard to the heat flow density that can be dissipated. In particular, aerodynamically optimized designs of the air supply device for utilizing physical, i.e. flow-mechanical effects are conceivable and offer the advantage of implementing different cooling concepts.With regard to the air supply device, it is advantageous if this is designed as a detachable or non-detachable cover / as a housing for the outside of the heat exchanger. For the preferably loss-free supply of the air, it is advantageous if the dimension of the air supply device is substantially designed in the size of the outer side of the heat exchanger and seals it with respect to the E axis. Via the provided inlet and outlet, an advantageous air guidance / defined air flow can be realized in a preferably predetermined manner depending on the cooling principle realized. The term "substantially" refers to the inlet and outlet exceeding the dimension of the outside of the heat exchanger.The embodiment as a detachable cover offers advantages with regard to the replacement of the air supply device after wear or damage and the protection of the heat exchanger against damage from the environment of the e-motor vehicle in the underbody region. In addition, it is advantageously possible from a cost standpoint to produce the air supply device, which is designed as a detachable cover, from a cost-effective material such as plastic.Furthermore, it is advantageous from the manufacturing and assembly points of view within the meaning of the technical invention to design the air supply device alternatively as a fixed / non-detachable component of the underbody / the underbody cladding or as a part of the underbody cladding, or as a part of the underbody cladding, wherein it is likewise possible to advantageously realize the protection of the heat exchanger against damage from the environment of the electric motor vehicle in the underbody region.In connection with the air supply device, it is likewise advantageous to connect it to the housing of the E-axle / an E-axle system in the sense of a compact and easily assembled design of the E-axle.Furthermore, it is advantageous if the air supply device has at least one duct which is aligned substantially in the direction of the longitudinal extent of the underbody cladding and into which the heat exchanger projects or has a multiplicity of ducts which are separated from one another by ribs and through which air can be directed from or to the heat exchanger during operation.In the case of the at least one duct, which is preferably oriented in the longitudinal direction and does not buckle in another direction, the openings of the air supply device for the air inlet and the air outlet for the air supply orientation are preferably at least partially or completely parallel to one another and at least partially or completely at a height with respect to one another, so that a direct air flow can be realized. The unidirectional alignment of the channel is advantageous in particular with regard to the uniform heat dissipation from the outside of the heat exchanger, which protrudes into the channel or at least adjoins the latter in a flush manner.Advantageously, in terms of the air flow around, the heat exchanger preferably does not protrude into the duct with its outer side, viewed in the height direction, as far as the duct base. Furthermore, the channel is preferably arranged on the underside of the underbody cladding, so that the air flow occurring as a result of the movement of the electric motor vehicle is guided through the channel directly and without flow losses.Moreover, it is also conceivable within the meaning of the technical invention for a channel to be oriented in one direction, such as in the longitudinal direction, and to have a bending course in another direction, such as preferably in the height direction. The technical advantage of the bending or inclined course results in the fact that the air inlet and the air outlet of the air supply device can be realized at different heights. As a result, pressure differences of different air layers, preferably the air flow / air layer that occurs below the underbody as a result of the movement of the e-motor vehicle, and the air / air layer above the underbody cladding, can be advantageously utilized for implementing cooling concepts.In the sense of the solution according to the invention, it is likewise conceivable for the air inlet and / or the air outlet of the air supply device to be designed via a plurality of ducts, as a result of which local guidance of the air flow in individual duct regions can be implemented in a technically advantageous manner. The individual channels are advantageously separated from one another by ribs from the manufacturing points of view and from the flow / aerodynamic points of view. By means of the arrangement of the ribs, the flow type can preferably be influenced in the sense of non-laminar or turbulent flow and / or pressure differences can preferably be utilized. In addition, the mechanical strength of the air supply device in the region of the ribs is increased by the ribs.If a plurality of channels are provided, which are preferably oriented obliquely in the height direction to the direction of travel / direction of the air flow, and if the individual channels are preferably arranged next to one another or offset in the transverse direction, it is possible to realize the ambient air flow in a technically advantageous manner to utilize it to realize cooling concepts.It has proven advantageous if the ribs are designed as curved lamellae. The design of the ribs as curved lamellae is advantageous from an aerodynamic point of view. The embodiment generally characteristic of lamellae as narrow and thin elements results in advantageous design possibilities with regard to shape and alignment. In particular, flow-dynamic and in particular aerodynamically advantageous, curved or beveled blades can be realized. By means of this design of the ribs, effects such as non-laminar or turbulent flows and / or intake pressures and / or predetermined flow directions can be achieved in an advantageous manner and can be used advantageously for cooling concepts. The air flow can be steered in a targeted manner and can be adjusted / influenced in an advantageous manner with regard to the heat dissipation.It is furthermore advantageous if the air supply device is designed as a ventilation grille.Manufacturing advantages can be achieved by the embodiment as a ventilation grille, since the louvers and the air supply device constitute a manufacturing unit, the louvers are reproducibly brought into contact with the air supply device or are pre-assembled, and manufacturing of the ventilation grilles in series can be advantageously realized. By configuring the air supply device as a ventilation grille, simple and position-independent mounting, for example in the underbody cladding or on the outer side of the heat exchanger of the E-axle, can be advantageously realized.In addition, it is advantageous if the ventilation grille is inserted or can be inserted flush with the underside and / or the upper side of the underbody cladding and can preferably be integrated or is integrated into the E-axis. The arrangement of the ventilation grille flush with the underside of the undercover is advantageous from the flow-mechanical and in particular aerodynamic points of view and for protecting the ventilation grille from damage from the environment of the e-motor vehicle from the underside / the underbody protection. The arrangement flush with the upper side of the underbody cladding offers the advantage that no installation space is applied above the underbody cladding for the placement of the grille and advantageous positioning of the outer side of the heat exchanger can be realized in a space-saving manner in the region of the ventilation grille. It is likewise conceivable to position the air supply device designed as a ventilation grille directly on the heat exchanger. By means of the simple integration of the ventilation grille into the E-axis from the standpoint of assembly, an advantageous compact design of the E-axis results.In addition, it has proven to be advantageous if the slats are all opened / inclined in the direction of the direction of travel or counter to the direction of travel. The orientation of the slats in the direction of travel is to be understood as meaning that the slats are inclined / beveled towards the direction of travel. The upper boundary region of the slat as viewed in the height direction is situated in front of the lower region of the slat as viewed in the height direction and thus as viewed in the direction of travel. When the slats are oriented counter to the direction of travel, the slats are inclined counter to the direction of travel. The upper boundary region of the slat as viewed in the height direction lies behind the lower region of the slat as viewed in the height direction and thus as viewed in the direction of travel. The extent of the lamellae is not influenced thereby. The slats have the greatest dimension in the transverse direction.By means of the preferably uniform alignment of the fins, different cooling principles can be realized in the sense of a predetermined air supply to the base plate of the heat exchanger / to the heat exchanger based on technical effects. Due to the orientation of the fins against the direction of travel, a forced air flow can be achieved directly in the direction of the heat exchanger. If the plates are inclined in the direction of travel, the air is drawn in directly to the heat exchanger / the base plate of the heat exchanger.With regard to the lamellae, for monitoring the air volume flowing into the air supply device, it is furthermore advantageous, preferably depending on the waste heat to be dissipated or the transferable heat density at different operating points and temperatures (operating temperature of the E-axis and / or ambient temperature), if an electrical actuation and, as required, closing of the lamellae can be realized.To increase the mechanical strength of the ventilation grille and thus of the air supply device, one or more reinforcing struts are preferably provided, which are aligned orthogonally to the ribs separated from one another and are connected to a frame of the ventilation grille.It has also proven advantageous if the heat exchanger has a plurality of metal strips. The plurality of metal strips makes it possible, on the one hand, to realize an advantageous heat transport into the metal strips due to the high thermal conductivity of the metal. In addition, the thin metal strips provide a multiplicity of free surfaces via which the heat is preferably convectively emitted to the air flowing past the surfaces and is discharged with the latter from the heat exchanger / the E-axis.It is advantageous if the metal strips are configured flat. The extensive embodiment of the metal strips advantageously enables convective heat transfer to be realized over a large area, as a result of which the dissipated heat flux density is advantageously increased compared to a non-extensive embodiment.It is furthermore advantageous if the E-axis is prepared for fluidless operation. The fluidless operation is understood to mean that the air-cooled E-axle is without connection to the cooling circuit of the E-vehicle. The fluidless operation does not exclude that the air cooled E-axle is lubricated with oil inside.By not providing the E-axis connection to the vehicle cooling system, heat dissipation to ambient air is the only solution for cooling the E-axis. As a result, the cooling concept of the air-cooled E-axle is particularly advantageous since it provides the heat dissipation to the ambient air as a technical solution.The E-axis is furthermore advantageously designed in such a way that the heat dissipation from the base plate of the heat exchanger by the air flowing past brings about advantageous cooling of the E-axis.The invention is explained in more detail below with the aid of a drawing. Four preferred embodiments of the air cooled E-axis are shown.For the air cooled E-axis according to the invention, a first, simple embodiment and two aerodynamic embodiments are explained depending on the ventilation grille shape. The two aerodynamic embodiments are divided into a second embodiment with lamellae inclined in the direction of travel and a third embodiment with lamellae inclined counter to the direction of travel. The embodiments conform to three cooling concepts. The first embodiment corresponds to a simple, direct flow-through-based cooling concept. Via the second embodiment, an intake-based cooling concept is realized. The third cooling concept is based on forced flow and is implemented via the third embodiment.The three embodiments can furthermore be combined with three embodiments of the introduction of the air supply device into the E-axis. These are a first embodiment which provides for the attachment of the air supply device to the heat exchanger and the introduction into a through-opening in the underbody cladding with flush termination to these (aerodynamic embodiments two and three). A second embodiment of the introduction, which provides the introduction into the underbody cladding with projections through the underbody cladding (simple embodiment one). In addition, the third embodiment is based on a complete integration of the air supply device into the underbody cladding of the e-motor vehicle (aerodynamic embodiment three).The following are shown: FIG. 1 shows a perspective illustration of a first embodiment of an air-cooled E-axis with aerodynamic design of the air supply device, flush integration into a through opening and an air inlet oriented counter to the direction of travel in an exploded view in a side view, FIG. 2 shows a perspective illustration of the underbody cladding and of the air supply device of an air-cooled E-axle according to FIG. 1, which is integrated into the underbody cladding via a passage opening, in a view from below, FIG. 3 shows a perspective illustration of the air supply device of the air-cooled E-axle according to FIG. 1, shown in detail, in an enlarged illustration without underbody cladding, in a view from below, FIG. 4 shows a perspective illustration of the air supply device of the air-cooled E-axis according to FIG. 1, shown in detail, in a view from below, FIG. 5 shows a perspective illustration of the air guidance device, illustrated as a separate component, for a second embodiment of an air-cooled E-axis with fins inclined counter to the direction of travel for flush integration into a through-opening in a side view, FIG. 6 shows a perspective illustration of the air guidance device, illustrated as a separate component, with fins inclined in the direction of travel for a first embodiment of the air-cooled E-axis according to FIG. 1 or a third embodiment of the air-cooled E-axis according to FIG. 10, in a side view, FIG. 7 shows a perspective illustration of the air supply device of the air-cooled E-axle according to FIG. 1 or FIG. 5, which is illustrated in detail, arranged on a heat exchanger and without underbody cladding, in a detailed view from the opposite direction of travel, FIG. 8 shows a perspective illustration of the air supply device of the air-cooled E-axle according to FIG. 1, shown in detail, with a heat exchanger and without an underbody cladding, as an exploded drawing, in a lateral view from below, FIG. 9 shows a perspective illustration of a detail of the outer side of the heat exchanger for an air-cooled E-axis in a detailed view of the metal strips from below, FIG. 10 shows a schematic illustration of the course of the air flow for a heat exchanger, illustrated as a separate component, for a third embodiment of an air-cooled E-axis with aerodynamic design of the air supply device, fins inclined in the direction of travel, flush integration into a through opening and an air inlet oriented in the direction of travel, in a lateral cross-sectional view, FIG. 11 shows a two-dimensional basic representation of the schematic profile of the air flow for the embodiment of the heat exchanger for an air-cooled E-axis according to FIG. 10 shown as a separate component in a cross-sectional view, FIG. 12 shows a perspective illustration of a detail of an air-cooled E-axis in an embodiment according to FIG. 1, FIG. 5 or FIG. 10 with an air heat exchanger in a detail detail detail view in a side view, FIG. 13 shows a schematic illustration of the air flow through an air supply device for a fourth embodiment of an air-cooled E-axis in a simple embodiment of the air supply device and introduction into the underbody cladding with projections through the underbody cladding in a two-dimensional side view, FIG. 14 shows a schematic illustration of the air flow below the underside of the underbody cladding for an air-cooled E-axis according to FIG. 13 in a two-dimensional plan view from below, FIG. 15 shows a perspective illustration of an oil-air heat exchanger, illustrated as a separate component, with an air supply device for an air-cooled E-axis according to FIG. 13 in an exploded illustration in a side view, and FIG. 16 shows a perspective illustration of an underbody cladding, illustrated as a separate component, for a fifth embodiment of an air-cooled E-axle with an aerodynamic design of the air supply device and an air guidance device integrated into the underbody cladding, in a plan view.The drawings are merely schematic in nature and serve only to understand the invention. The same elements are provided with the same reference numerals. The features of the individual embodiments may complement each other or may be substituted.FIG. 1 shows a perspective illustration of an air-cooled E-axle 1 in a first embodiment in an exploded view in a side view. The air-cooled E-axle 1 consists of an E-engine 2, a heat exchanger 3 arranged on an underside of the E-engine 2, and an underbody cladding 4. the underbody cladding 4 has a through-opening 5 in the form of a cutout, and an E-engine-side upper side 6 and an underside 7 facing away from the E-engine. The through-opening 5 is configured to receive an air supply device 8, so that the air supply device 8 can be arranged in the through-opening 5, for example according to FIG. 2.The air supply device 8 is designed in the form of an integrated air guidance system. The air supply device 8 represents a cover / ventilation grille and has on the underside a plurality of ducts 9 which are separated from one another by a plurality of ribs 10. The ribs 10 are designed as lamellae 10 and are inclined in the direction of travel 11 which corresponds to a longitudinal direction 23. The air supply device 8 is configured for releasably enclosing / surrounding the heat exchanger 3, which is embodied with a plurality of metal strips 12. The metal strips 12 are provided flat on a base plate 13 of the heat exchanger 3. A frame 14 of the air supply device 8 corresponds in dimension substantially to the base plate 13 of the heat exchanger 3. The air supply device 8 is configured to guide an air flow 15 (for example according to FIG. 8 ) to the heat exchanger 3, via which convective heat dissipation from the heat exchanger 3 to the air flow 15 takes place. The design of the air supply device 8 with fins 10 is referred to as aerodynamic.This first embodiment of the air-cooled E-axle 1 is characterized by the aerodynamic design of the air supply device 8, flush integration into a through-opening 5 and an air inlet 17 oriented counter to the direction of travel 11.It is likewise conceivable for the air supply device 4 to be connected to the housing / system housing of the air-cooled E-axle / air-cooled E-axle system 1 or the underbody cladding 4. In addition, the air supply device 8 can be designed as part of the underbody cladding 4 and thus be integrated directly therein and connected thereto. If the air supply device 8 is alternatively connected to the underbody cladding 4 merely in a positive and / or non-positive and / or materially bonded manner in the sense of a further embodiment, the underbody cladding 4 has a cutout which is designed as a through opening 5 and via which the air supply device 8 is configured.The heat exchanger 3 can likewise be a component of the system housing of the air-cooled E-axis / air-cooled E-axis system 1. Alternatively, it is conceivable for the heat exchanger to be designed as a separate component on or in an underbody / underbody cladding 4 of the air-cooled electric axle 1.FIG. 2 shows a perspective illustration of an air-cooled E-axle 1 according to FIG. 1 in a view from below onto the underside 7 of the underbody cladding 4. The air supply device 8 is integrated into the underbody cladding 4 via a through-opening 5. The electric motor 2 is positioned on the side facing away from the underbody cladding 4. The air supply device 8 is arranged in one of the through-openings 5 and terminates flush with the underside 7 of the underbody cladding 4. The air supply device 8 is thus integrated in a compact and fluidically / aerodynamically advantageous manner into the air-cooled e-axle 1. On the frame 13 of the air supply device 8, a plurality of ribs 10 are arranged in the form of lamellae in the embodiment. The ribs 10 separate a plurality of channels 9 and form them via the separation. Between the ribs 10 a plurality of reinforcing struts 16 are arranged in the longitudinal direction 23 in order to increase the mechanical strength of the air supply device 8 in the region of the ribs 10. The ribs 10 are chamfered and inclined in the direction of travel 11 which corresponds to the longitudinal direction 23. By orienting the ribs 10 in the direction of travel 11, the air flow 15 takes place by drawing in the ambient air, preferably as a result of pressure gradient forces, to the heat exchanger 3, not shown (for example according to FIG. 1 ).FIG. 3 shows an air supply device 8 of an air-cooled E-axle 1 according to FIG. 1 in an enlarged illustration without an underbody cladding 4 in a view from below. The air supply device 8 is shown as a system housing for the heat exchanger 3. In addition to the frame 14 on which the ribs 10 are arranged and the reinforcement struts 16 arranged orthogonally thereto, which increase the mechanical strength of the air supply device 8, an opening is provided on the air supply device 8, which opening can be configured as an air inlet 17 and an air outlet 18 for air flow 15. The air supply device 8 covers the heat exchanger 3, the base plate 13 of which consists of metal strips 12 arranged in a planar manner. The air can advantageously flow around the metal strips 12, so that the preferably convective heat input from the heat exchanger 3 can advantageously take place.FIG. 4 shows a perspective illustration of a detail of the underside 7 of the air-cooled E-axle 1 according to FIG. 1 with heat exchanger 3 and air supply device 8 in the through-opening 5 of the underbody cladding 4 in a view from below. Beyond the illustration in FIG. 2, which shows a slightly different perspective, the reinforcing struts 16 and the flat metal strips 12 of the base plate 13 of the heat exchanger 3 are illustrated in detail. The technical effects of the structural features correspond to those shown in FIG. 3.FIG. 5 shows a perspective illustration of the air guidance device 8, illustrated as a separate component, for a second embodiment of an air-cooled E-axle 1 with fins 10 inclined counter to the direction of travel 11 for flush integration into a through-opening 5 in a side view. The air outlet 18 is located on a rear side, as viewed in the direction of travel 15, of an air-cooled E-axle 2, not shown (for example according to FIG. 1 ), and therefore opposite the direction of travel 11 and above the upper side 6 of the underbody cladding 4. The frame 14, the reinforcing struts 16 of the air supply device 7 correspond to the elements illustrated in FIGS. 3 and 4. The ribs 10 are inclined counter to the direction of travel 11, whereby a forced air flow 15, not shown, is realized directly in the direction of the heat exchanger 3, also not shown (for example according to FIGS. 1, 3 or 4 ). The direction of the forced air flow 15 on the underside 7 of the underbody cladding 4 is directed opposite the direction of travel 11. The air flow 15 brings about the heat dissipation from the heat exchanger. This is the third embodiment of a cooling concept via forced air flow 15.FIG. 6 shows a perspective illustration of the air guidance device 8, illustrated as a separate component, with fins 10 inclined in the direction of travel 11 for a first embodiment of the air-cooled E-axle 1 according to FIG. 1 or a third embodiment of the air-cooled E-axle 1 according to FIG. 10 in a side view. Depending on the embodiment, the air inlet 17 is arranged above the underbody cladding 4 in (first embodiment of the air-cooled E-axis 1) or opposite (third embodiment of the air-cooled E-axis 1) to the direction of travel 11. In principle, it is also conceivable for the air inlet 17 to be arranged on each side of the air-cooled E-axis 1 and thus in, counter to or transversely to the direction of travel 11. By the orientation of the ribs 10, the second embodiment of the cooling concept is realized, which is based on the principle of the air flow 15 as a result of the intake of air. The air flow 15 to the heat exchanger 3 is realized via the ribs 10 inclined in the direction of travel 11 by suctioning the air 15 from the environment under the underside 7 of the underbody cladding 4 to the heat exchanger 3, not shown (for example according to FIGS. 1, 3 or 4 ). The ribs 10 are preferably designed as thin lamellae, by means of which a low flow resistance is realized. Between the louvers 10 the channels 9 for the air flow 15 are shown, which are configured as air inlet 17 of the air flow 15 into the air supply device 8. By means of the plurality of channels 9, an advantageous, defined flow of the air 15, which is not shown, can be realized. In addition, the air flow 15 can be adjusted and steered via the curved shape of the fins predetermined from the flow / aerodynamic points of view and their arrangement with respect to one another, which promotes the heat removal from the heat exchanger 3. The air flow 15 carrying the waste heat leaves the feed device counter to the direction of travel 11, which is illustrated in the longitudinal direction 23 via the air outlet 18.FIG. 7 shows a perspective illustration of the air supply device 1 of the air-cooled E-axle 1, which is illustrated in detail, as a function of the not-illustrated orientation of the fins according to FIG. 1 (first embodiment of the air-cooled E-axle 1 with fins inclined in the direction of travel) or FIG. 5 (third embodiment of the air-cooled E-axle 1 with fins inclined counter to the direction of travel) arranged on a heat exchanger 3 and without underbody cladding 4 in a detailed view from counter to the direction of travel 11. The air supply device 8 is shown as a system housing for the heat exchanger 3. The air flow 15 from the heat exchanger 3 to the environment, vice versa, is possible via the air inlet 17 or the air outlet 18. The design of the opening shown as air inlet 17 (first embodiment of air-cooled E-axis 1) or air outlet 18 (third embodiment of air-cooled E-axis 1) is determined by the implemented cooling concept / the orientation of the fins 10. The air inlet 17 or the air outlet 18 are located above the upper side 4 of the underbody cladding 4. the air inlet 17 can be oriented not only counter to the direction of travel 11 and thus toward the rear side of the E-axis, as shown, but can be located on each side of the E-axis. The air outlet 18 can only be formed on the rear side of the air-cooled E-axis as shown.FIG. 8 shows a perspective illustration of the air supply device 8 of the air-cooled E-axle according to FIG. 1, shown in detail, with a heat exchanger 3 and without an underbody cladding 4, as an exploded drawing in a side view from below. It is shown that the air supply device 8 represents a cover which images the shape of the heat exchanger 3 and which has openings for the air inlet 17 and the air outlet 18 of the air flow 15. The air supply device 8 is designed as a housing of the heat exchanger 3 and thus as a housing of an E-axle system.FIG. 9 shows a perspective illustration of a detail of the outer side of the base plate 13 of the heat exchanger 3 for an air-cooled E-axis 1 in a detailed view from below of the metal strips 12. The heat exchanger 3 shown in detail is shown as a separate component.FIG. 10 shows a schematic illustration of the course of the air flow 15 for a heat exchanger 3, illustrated as a separate component, for a third embodiment of an air-cooled E-axis 1 with an aerodynamic design of the air supply device 8, fins 10 inclined in the direction of travel, flush integration into a through opening 5 and air inlet 18 aligned in the direction of travel 11 in a lateral cross-sectional view. The heat exchanger 3 is designed as a separate oil-air heat exchanger. This means that the heat exchanger 3 is attached as a separate component to the underbody or to the underbody cladding 4 of the air-cooled electric axle 1. By attaching the heat exchanger 3 according to the embodiment, it is advantageously possible to introduce ribbing also on the inside of the air-cooled E-axis 1 via the oil cooling ribs 19 with regard to the oil discharge. The oil can advantageously easily drain off via the oil cooling ribs. The inside of the air-cooled E-axle 1 corresponds to the top 6 of the underbody trim 4.The air supply device 8 encloses the heat exchanger 3 in the manner of a cover and is designed aerodynamically, i.e. with fins 10. It can be seen from the illustration that the air supply device 8 terminates flush with the base plate 13 of the heat exchanger 3 in order to enable a defined / predetermined air flow 15 for heat dissipation. In the aerodynamic embodiment, the air supply device 8 is configured with fins / fins 10 configured in the manner of fins, which are arranged in the direction of travel 11. The air flow 15 is guided to the heat exchanger 3 via the air inlet 17 of the air supply device 8 and flows past the metal strips 12 arranged in a planar manner, which are arranged on the outer side of the heat exchanger 3, via a circulation chamber 20 of the heat exchanger 3. The air inlet 17 is oriented in the direction of travel 11 and is thus directed against the air flow 15 on the underside 7 of the underbody cladding 4. The air flow 15 takes place from the region above the upper side 6 of the underbody cladding 4 into the air inlet 17 by suction in the sense of the second embodiment of the cooling concept.On the metal strips 12 of the heat exchanger 3 arranged in a planar manner, which have a high surface temperature on account of the heat conduction of the waste heat from the not-shown electric motor 2 of the air-cooled electric axle 1 (for example according to FIG. 1 ), the convective heat dissipation takes place via the air flow 15. the air flow 15 carrying the waste heat passes via the plurality of ducts 9, which are separated by ribs 10 designed as fins and are designed as air outlet 18, out of the air supply device 8 into the environment of the not-shown electric motor vehicle below the underbody cladding 4. The air currents 15 mix.Beyond the convective dissipation of the heat beyond the air flow 15, the heat exchanger 3 is designed with oil cooling fins 19 on the inner side of the base plate 13. The oil cooling fins 19 can also be designed as oil cooling fins 19 and are provided for the heat exchange with oil on the inside of the heat exchanger 3. The inside of the heat exchanger 3 faces the unillustrated E-engine 2 (for example, as shown in FIG. 1 ) and represents the inner system boundary of the heat exchanger 3 toward the system housing of the air-cooled E-axis 1, more specifically, the E-engine 2. A wire mesh, not shown, or also planar metal strips 12 (for example according to FIG. 9 ) may be introduced between the oil cooling ribs / oil cooling fins 19 on the inside of the heat exchanger 3 in order to increase the surface area and to enable an advantageously improved heat dissipation via the air flow 15. The present cooling concept is explained in more detail in connection with FIG. 11. The oil fins 19 need not be arranged parallel to each other, but may be at an angle to each other. Alternative embodiments are likewise conceivable. The use of a wire netting is advantageous in particular in connection with aerodynamic embodiments of the air supply device 8, such as the one explained for FIG. 10. The wire mesh does not completely fill the space between the oil cooling fins 19 in order to advantageously allow the flow of oil for heat dissipation.The metal strips 12 arranged on the outside of the heat exchanger 3 can also be designed as air cooling fins 21 or air cooling fins 21. In particular for the embodiment as air cooling fins 21, the combined arrangement of metal bands 12 or a wire mesh, not shown, in correspondence with the oil cooling fins 19 on the inside of the heat exchanger 3 is advantageous in order to increase the free surface area, via which a heat dissipation can take place. The air cooling fins / air cooling fins 21 do not have to be arranged parallel to one another, but can be arranged offset from one another at an angle, so that the individual air cooling fins / air cooling fins 21 can be arranged at different, predetermined angles to one another. The wire mesh advantageously does not completely fill the space between the air cooling ribs 21 in the sense of the air flow and the heat dissipation.FIG. 11 shows a two-dimensional principal illustration of the schematic profile of the air flow 15 for the embodiment of the heat exchanger 3 for an air-cooled E-axis 1 according to FIG. 10, which is illustrated as a separate component, in a cross-sectional view. The second cooling concept on which this embodiment is based provides that air 15 does not flow directly against the heat exchanger 3. Rather, a negative pressure is used which is produced by the pressure difference of the air flow 15 at the underside 7 of the underbody cladding 4 and thus below the non-illustrated electric motor vehicle and the air above the underbody cladding 4 in front of the air inlet 17. Due to pressure gradient forces which are established as a result of the pressure difference, the air at the air inlet 17 is sucked into the air supply device 8.The heat exchanger 3 is designed as a separate component and as an oil-air heat exchanger. In principle, further embodiments of the heat exchanger 3 in combination with an integrated air supply device 8 are conceivable. The air flow 15 to the heat exchanger 3 is achieved by the intake of air from the region above the upper side 6 of the underbody cladding 4 into the air inlet 17.For the described second embodiment of the cooling concept, a certain distance, a so-called circulation space 20, is required so that the incoming air 15 can collect above the metal bands 12 and / or preferably the wire mesh, in order to be subsequently sucked through the metal bands 12 and / or the wire mesh arranged in a planar manner.The air flow 15 is also effected through the wire mesh. According to the embodiment, the air inlet 17 is arranged such that the air can be sucked in above the upper side 6 of the underbody cladding 4. The air inlet 17 is located in an area above the top side 6 of the underbody cladding 4. the air inlet 17 may be located on either side of an unillustrated air cooled E-axis 2 as viewed in the longitudinal direction 23.It is also conceivable, within the meaning of a further embodiment, to direct the air flow 15 directly through the heat exchanger 3. In this case, the air supply device 8 is arranged at least partially below the underside 7 of the underbody cladding 4, such that the air flow 15 prevailing there and directed opposite the direction of travel 11 is directed directly into the air supply device 8. This conceivable embodiment is detailed in FIGS. 13, 14 and 15.FIG. 12 shows a perspective illustration of a detail of an air-cooled E-axle 1 in an embodiment according to FIG. 1 or 10 with an air supply device 8 in a detail detail view in a side view. The air inlet 17 or air outlet 18 is arranged on the rear side of the E-axis opposite to the direction of travel 11. The air supply device 8 is arranged in a through-opening 5.FIG. 13 shows a schematic illustration of the air flow 15 through an air supply device 8 for a fourth embodiment of an air-cooled e-axle 1 in a simple embodiment of the air supply device 4 and introduction into the underbody cladding 4 with projections through the underbody cladding 4 in a two-dimensional side view. The illustration schematically illustrates the first embodiment of the cooling concept for an air-cooled E-axle 1, which is not illustrated. The heat exchanger 3 (for example according to FIG. 15 ) which is not shown is arranged above the air supply device 8 and can project at least partially into the latter. The air supply device 8 is arranged in the through opening 5 in the underbody cladding 4 and, in the embodiment shown, terminates flush with the upper side 6 of the underbody cladding 4. The air flow 15 below the underbody cladding 4 is directed opposite the direction of travel 11 and flows directly from the air inlet 17 into the air supply device 8 and past an outer side, not shown, of the heat exchanger 3 with convective heat dissipation. The air flow 15 carrying waste heat leaves the air supply device 8 via the air outlet 18, the air supply device 8 being designed with at least one duct 9 which is oriented in the longitudinal direction 23 and preferably extends horizontally. Alternatively, multi-channel designs of the air supply device 8 are conceivable.FIG. 14 shows a schematic illustration of the air flow 15 below the underside 7 of the underbody cladding 4 for an air-cooled E-axis 1 according to FIG. 13 in a two-dimensional plan view from below.FIG. 15 is a perspective illustration of a heat exchanger 3, illustrated as a separate component, with an air supply device for an air-cooled E-axis according to FIG. 13 as an exploded illustration in a side view. The heat exchanger 3 is designed as an oil-air heat exchanger. The air supply device 8 is shown as a system housing of the heat exchanger 3. On the inside of the heat exchanger 3, oil fins 19 for heat exchange with oil as a cooling medium are disposed on the base plate 13 of the heat exchanger 13. The oil cooling fins 19 can likewise be designed as additional oil cooling fins 19 in order to ensure better heat exchange with the oil in the oil sump.The base plate 13 is provided for mounting on a lower side of the electric motor 2 (for example according to FIG. 1 ). The base plate 13 is to be sealed off from the electric motor 2, not shown. In addition, the base plate 13 rests on the frame 14 of the air supply device 8. The air supply device 8 terminates flush with the base plate 13 in order to achieve a seal. The air supply device 8 is designed as a simple / simplified air supply device 8 without lamellae 10. For the end flush with the base plate 13, a sealing lip 22 aligned parallel to the base plate 13 is provided on the frame 14 of the air supply device 8 in the upper region. On the outside of the base plate 13 of the heat exchanger 3, a plurality of thin air fins 21 arranged transversely to the direction of alignment of the oil fins 19 are provided for heat exchange with the ambient air. The individual air cooling fins 21 of the plurality of air cooling fins 21 are spaced apart from each other. By the distance of the air cooling ribs 21 from each other, a plurality of channels 9 are formed. Air 15 flowing in from the air inlet 17 of the air supply device 8 can flow through the channels 9 in a guided manner to the air outlet 18 and can remove heat from the air cooling ribs 21 by convective heat transfer. The height of the air cooling fins 21 of the heat exchanger 3 is less than the dimension of the air supply device 8 in the height direction 25 As a result of this embodiment, the convective heat transfer from the air cooling fins 21 to the air flow 15 can be effected by the air flow 15 flowing past the air cooling fins 21 according to the first embodiment of the cooling concept for an air-cooled E-axis 1, which is not illustrated.FIG. 16 shows a perspective illustration of an underbody cladding 4 shown as a separate component for a fifth embodiment of an air-cooled E-axle 1 with an aerodynamic design of the air supply device 8, slats 10 inclined counter to the direction of travel 11 and an air guidance device integrated into the underbody cladding 4 in a plan view.In this embodiment, the air supply device 8 is an integral component of the underbody cladding 4 and thus also of an air-cooled E-axle 1 according to the invention, which is not illustrated. The frame 12 of the air supply device 8 protrudes flush on the upper side 6 of the underbody cladding 4 or protrudes therefrom. If the air guidance device 8 is not directly integrated into the underbody cladding 4 and is connected thereto, a cutout designed as a through opening 5 is provided, into which the air guidance device 8 is integrated. The through-opening 5 of the underbody cladding 4 is thus sealed. Provided on the frame 12 at the level of the through-opening 5 of the underbody cladding 4 are lamellar, beveled and inclined against the direction of travel 11 ribs / slats 10, which are connected by reinforcing struts 16. Via the beveled, lamellar ribs 10, an air flow 15 is forced into the air supply device 8. The forced air flow 15 characterizes the third embodiment of the cooling concept for air-cooled E-axles 1. The channels 9 between the ribs 10 are thus designed as air inlet 17 for the air flow 15. The frame 12 of the air supply device 8 is furthermore designed to receive the base plate 13, not shown, of the heat exchanger 3 (for example according to FIG. 10 ), so that the convective heat dissipation takes place by the air flow 15 which is guided past the lower side of the base plate 13, on which metal strips 12 and / or wire netting (for example according to FIG. 9 ) which are not shown can be arranged. The air flow 15 carrying the waste heat exits the integrated air supply device 8 via the air outlet 18. The air outlet 18 is arranged opposite the direction of travel 11. By means of variably adjustable ribs 10 in the form of fins 10, other cooling concepts (for example according to the description relating to FIG. 6 ) based, for example, on the intake of air can be realized.List of reference characters1 Air-cooled E-axle 2 E-engine 3 Heat exchanger / base plate of the heat exchanger 4 Underbody cladding 5 Through opening 6 E-engine-side upper side / upper side 7 E-engine-averted lower side / lower side 8 Air supply device / integrated air supply device / integrated air supply system / cover 9 Duct 10 Ribs / lamellar ribs / fins 11 Direction of travel 12 Metal strip / planar metal strip 13 Base plate 14 Frame 15 Air flow / flow of air 16 Reinforcing strut 17 Air inlet / inlet 18 Air outlet / outlet 19 Oil cooling ribs / oil cooling fins 20 Circulation space 21 Air cooling ribs / air cooling fins 22 Sealing lip 23 Longitudinal direction 24 Transverse direction 25 Height direction

Claims

Air-cooled E-axle (1) for a motor vehicle drive, wherein the air-cooled E-axle (1) consists of an E-engine (2), a heat exchanger (3) arranged on an underside of the E-engine (2) and an underbody cladding (4), wherein the E-engine (2) is in thermal coupling with the heat exchanger (3) designed for air cooling during operation, wherein the underbody cladding (4) has a through opening (5) for an air supply of the heat exchanger (3) and an air supply device (8) is fitted in the through opening (5) in order to supply air to the heat exchanger (3) during operation, wherein the heat dissipation from a base plate (13) of the heat exchanger (3) takes place by the air flowing past and brings about the cooling of the E-axle (1).Air-cooled E-axle (1) according to Claim 1, characterized in that the through-opening (5) is configured either for passing air through between an upper side (6) of the underbody cladding (4) on the E-engine side and an underside (7) of the underbody cladding (4) facing away from the E-engine side, or for receiving the heat exchanger (3) when it projects through the underbody cladding (4) from the upper side (6) thereof to the underside (7) thereof.Air-cooled E-axle (1) according to Claim 1, characterized in that the air supply device (8) has at least one duct (9) which is aligned substantially in the direction of the longitudinal extent of the underbody cladding (4) and into which the heat exchanger (3) projects or has a multiplicity of ducts (9) which are separated from one another by ribs (10) and through which air can be directed from or to the heat exchanger (3) during operation.Air-cooled E-axis (1) according to Claim 3, characterized in that the ribs (10) are designed as curved lamellae.Air-cooled E-axle (1) according to one of Claims 1 to 4, characterized in that the air supply device (8) is designed as a ventilation grille.Air-cooled E-axle (1) according to one of Claims 4 and 5, characterized in that the slats are all open in the direction of the direction of travel (11) or counter to the direction of travel (11).Air-cooled E-axis (1) according to one of Claims 1 to 6, characterized in that the heat exchanger (3) has a multiplicity of metal strips (12).Air-cooled E-axle (1) according to Claim 7, characterized in that the metal strips (12) are configured in a planar manner.Air-cooled E-axle (1) according to one of Claims 1 to 8, characterized in that the E-axle (1) is prepared for fluid-free operation.

Images