Vehicle drive for vehicle

Abstract

The invention relates to a vehicle drive (8) of a vehicle, comprising an electric machine (18), a transmission unit (44) and an eddy current brake (20) integrated in a hub region (22). The eddy current brake (20) has a rotor (40) which can be released by the flow of the air flow (58) by means of a closure cap (26) which is actuated by means of an annular closure element (24). The invention further relates to the use of a vehicle drive (8) in an electrically driven vehicle or a hybrid vehicle.

Description

TECHNICAL FIELD

[0001] The invention relates to a vehicle drive for a vehicle, having an electric machine, a transmission unit and an eddy current brake integrated in the wheel hub region. Furthermore, the invention relates to the use of the vehicle drive in an electrically driven vehicle or a hybrid vehicle. BACKGROUND

[0002] WO 2006 / 027056 A1 relates to a brake device having a rotor and a stator, wherein the rotor and the stator are arranged relative to one another and can be supplied or switched on with a working medium in such a way that a brake torque is transmitted from the rotor onto the stator in the event of a brake operation with the supplied or switchable working medium. The brake device comprises a fan wheel which can be switched on and off the drive connection with the rotor by switching on and off a coupling. The fan wheel is constructed and arranged in such a way that it supplies the brake device with a cooling airflow in the event of the fan wheel being switched on the drive connection with the rotor. The coupling is arranged and loaded with the working medium in such a way that the switching on and off of the working medium automatically causes the switching on and off of the coupling.

[0003] DE 1 918 832 A1 relates to an eddy current brake, the armature of which forms part of a rotor, which is provided with a reinforcing structure which facilitates the cooling of the rotor, wherein the reinforcing structure serves as a fan blade. There are provided closure elements which prevent air from flowing through the passages between the reinforcing structures when the brake is not in operation. The closure elements in their open position form respective aerodynamic braking faces outside the area swept by the reinforcing structures during the movement of the rotor, so that these closure elements in their open position form respective aerodynamic braking faces outside the area swept by the ribs during the movement of the rotor. In their closed position, the totality of the closure elements forms a rotation body having a negligible aerodynamic resistance in a manner known per se.

[0004] DE 10 2023 211 893 A1 relates to a vehicle drive for a vehicle, having a wheel, a transmission with an input shaft and an output shaft, wherein the output shaft is coupled to the wheel in order to drive the wheel with an output rotational speed, a brake device, and an electric motor, wherein the brake device and the electric motor are coupled to the input shaft or are arranged on the input shaft. The electric motor is configured to drive the input shaft with an input rotational speed N1, wherein the brake device is designed to brake the input shaft in order to reduce the input rotational speed N1, wherein the transmission is designed to transform the input rotational speed N1 into the output rotational speed N2.

[0005] The eddy current brake can replace the conventional disc brake hitherto used in the vehicle drive and is moreover wear-free and maintenance-free. The kinetic energy released during braking is recovered in electrically driven vehicles by means of the electric machine or converted into heat at the brake system. This heat can be released by friction or, as in the case of the eddy current brake, by eddy currents in the rotating brake disc (rotor). The thermal energy is discharged to the surroundings in order not to damage the surrounding components and in order to be able to absorb the subsequent braking energy.

[0006] A disadvantage of the rapidly rotating eddy current brake is the air friction of the rotating rotor of the eddy current brake. This rotor is continuously rotated even during unbraked straight-ahead travel. SUMMARY

[0007] According to the application, a vehicle drive of a vehicle is proposed, wherein the vehicle drive comprises an electric machine, a transmission unit and an eddy current brake integrated in the wheel hub region. The eddy current brake has a rotor which can be released by means of a cover element by means of the throughflow of an air flow, the cover element being assigned an annular closure element.

[0008] With the solution proposed according to the application, a very efficient heat dissipation of the eddy current brake of the vehicle drive can be achieved, as can also a minimization of the air friction between the rotating components and the stationary components of the vehicle drive.

[0009] In an advantageous design variant of the vehicle drive proposed according to the application, the rotor of the eddy current brake has a maximized surface with flow channels shaped like leaves. This design enables a very good heat conduction and a very efficient waste heat transport to the surroundings.

[0010] Furthermore, the vehicle drive proposed according to the application is distinguished in that the flow channels open into the outer peripheral surface of the rotor.

[0011] Furthermore, in the vehicle drive proposed according to the application it is provided that the flow channels open into slit-like channel openings of the outer peripheral surface. This shaping of the flow channels enables a minimization of the structural space parallel to the wheel hub.

[0012] In a further advantageous design variant of the vehicle drive proposed according to the application, an annularly configured closure element is received on the outer peripheral surface, which closure element can be moved between a closed position and an open position perpendicular to the circumferential direction of the outer peripheral surface. By means of the annular closure element the flow channels shaped like leaves of the rotor can be closed and opened.

[0013] In an advantageous manner, the vehicle drive proposed according to the application is obtained in such a way that the annular closure element can be moved or actuated electromechanically, hydraulically or by means of a bimetal spring.

[0014] In an advantageous manner, the vehicle drive according to the application is designed such that the annular closure element imparts a push travel to the closure cap which is substantially surrounded by the rotor, which push travel is identical to the push travel of the annular closure element when it is operated upon. The annular closure element and the closure cap can for example form an integral component at the outside. The closure can then be constructed such that it partially surrounds the housing and carries the annular closure element, or vice versa.

[0015] In an advantageous refinement of the vehicle drive according to the application, the annular closure element is operated in dependence on the temperature of the rotor. This can for example be achieved by using at least one bimetallic spring, whereby in the event of a temperature rise of the components of the eddy current brake, as can occur for example when driving downhill, the at least one bimetallic spring operates the closure element, so that the flow channel of the rotor of the eddy current brake having the largest surface is opened and swept through by the gas flow which is removed from the waste heat. The bimetallic spring is an example of a passive system, while a hydraulic or electromechanical actuator is an example of an active system.

[0016] In an advantageous manner, the annular closure element releases or closes the channel opening of the flow channel which is provided at the outlet side and is embodied in the form of a slit.

[0017] In a further advantageous refinement of the vehicle drive according to the application, in the closed position of the annular closure element, the closure cap which is embodied in the form of a taper abuts against the rotor, while in the open position of the annular closure element, the closure cap which is embodied in the form of a taper is detached from the rotor and deflects the gas flow through the opened flow channel towards the inside of the wheel.

[0018] Furthermore, the application relates to the use of the vehicle drive in an electrically driven vehicle, a passenger car, a utility vehicle or a rail vehicle.

[0019] Advantages of the application.

[0020] By the solution according to the application, the vehicle drive is provided with an eddy current brake which replaces the hitherto used conventional, hydraulically operated disc brake at the wheel. In particular, the eddy current brake is designed to be smaller and can be implemented not only wear-resistant but also maintenance-free. The kinetic energy which is released during braking of the electrically driven vehicle is recovered in the vehicle by means of the electric machine or converted into heat at the brake system. This heat can be released by friction or, as in the case of the use of an eddy current brake, by eddy currents in the rotating brake disc which behaves as a rotor.

[0021] By the solution according to the application of the fan wheel-like design of the rotor of the eddy current brake, a continuous gas flow can be guided through the rotor and the housing of the eddy current brake.

[0022] By means of the closure mechanism arranged at the inlet side or at the outlet side of the flow channel of the rotor of the eddy current brake, the air flow can be reduced or even interrupted. As a result, the rotor only moves the air in the brake housing which is only partially or even completely closed. As a result, lower air friction losses can be achieved than in the case of an open air feed and air discharge. The required power requirement is thus reduced again during driving with closed openings, so that the consumption of an electrically driven vehicle can be positively influenced, i.e. reduced. Furthermore, in the case of a closed opening at the inlet side and at the outlet side of the flow channel of the rotor, the noise emission of the rotating fan wheel can be reduced.

[0023] The shaping of the rotor of the eddy current brake increases its surface and its throughflow and thus can positively influence the cooling effect, i.e. the discharged heat flow. During rotation of the drive shaft, the surrounding air flows through the eddy current brake depending on the direction of rotation and the orientation of the rotor. The housing openings of the flow channel can be closed or opened depending on the cooling requirement. In the case of a cold eddy current brake, the throughflow and thus the air friction is minimized by closing the openings of the flow channel. Conversely, if the rotor is heated as a result of one or more braking processes, the throughflow of the flow channel of the rotor can be achieved by opening the flow channel.

[0024] The air flow for the throughflow of the flow channel of the rotor is hereby sucked in through the slit-like openings in the housing of the eddy current brake and discharged on the inside of the wheel from the rotor of the eddy current brake and vice versa, depending on the direction of rotation of the wheel.

[0025] This cooling of the eddy current brake can not only be integrated in a central drive or else in the drive and brake units arranged close to the wheel in the vehicle drives mentioned. The application is not limited to automobiles, but the vehicle drives according to the application can also be used in commercial vehicles and rail vehicles.

[0026] As an actuator for the manipulation of the air feed or for interrupting the air feed, for example, a passive system can be used, which can be represented, for example, by a bimetallic element which carries out a movement depending on the temperature present. A relatively simple and cost-advantageous actuator can be achieved thereby. However, as an alternative, it is also possible to use an active system in the form of an electromechanical or hydraulic actuator instead of a passive system in the form of a bimetallic element or bimetallic spring in order to allow or interrupt the air feed. BRIEF DESCRIPTION OF DRAWINGS

[0027] Embodiments of the application are explained in more detail according to the drawings and the following description.

[0028] in which: Figure 1A vehicle drive according to the application is shown in the installed state with closed air supply, Figure 2 A vehicle drive according to the application is shown in the installed state with open air supply, Figure 3 A sectional view through the components of a vehicle drive according to the application viewed in the driving direction with closed air supply in the installed state in the manner of an integrated wheel, Figure 4 A sectional view of a vehicle drive according to the application in the installed state with open air supply in the height of the wheel axle, and Figure 5.1 and Figure 5.2 The annular closure element and the closure cap as an integral component are shown in the open position or in the closed position. DETAILED DESCRIPTION

[0029] In the following description of embodiments of the application, identical or similar elements are denoted by the same reference signs, wherein in individual cases a repeated description of these elements is dispensed with. The drawings show the subject matter of the application only schematically.

[0030] Figure 1 An embodiment variant of a vehicle drive 8 according to the application is shown in the installed state with closed air supply. The vehicle drive 8 is preferably embodied as a single-wheel drive 9 which is embedded in a wheel rim 16.

[0031] It emerges from the perspective view according to Figure 1 that the vehicle drive 8 is arranged at a wheel 10 in the hub region 22 of the wheel. The wheel 10 comprises a wheel rim 16 on which a tyre is fitted, the tread of which is denoted by the reference sign 12. The vehicle drive 8 in the hub region 22 of the wheel 10 comprises an electric machine 18, of which only the housing is shown here, and a field brake 20 which is surrounded by the electric machine 18. The electric machine 18 can be embodied as a permanent-magnet synchronous machine (PSM) or as an asynchronous machine (ASM) or as an electrically excited synchronous machine (ESG). Both a motor-driven operation and a generator operation of the electric machine 18 are possible. Furthermore, it is identified that an annular closure element 24 is arranged on the outer peripheral surface 31. Furthermore, there is a closure cap 26 in the hub region 22, which is configured here, for example, funnel-like. It emerges from the perspective view according to Figure 1The wheel outer side is designated by reference 66 and the wheel inner side is designated by reference 68, which is arranged in a wheel house, wherein the wheel house is part of a vehicle, for example a passenger car (PKW), which is not shown here. The vehicle drive 8 according to the application can be used not only in passenger cars, but also in commercial vehicles or in rail vehicles. The vehicle drive is distinguished by a very compact design.

[0032] Similar to the illustration according to Figure 1 Figure 2 The vehicle drive 8 according to the application is shown as a drive of the wheel 10. In contrast to the illustration according to Figure 1 Figure 2 The vehicle drive 8 is shown in Figure 1 such that there is an open air feed 30. In contrast to the illustration according to Figure 2 In the case of the open air feed 30, the closed element 24, which is configured for example as a ring, is pushed out laterally by a lateral offset 32 on the outer circumference 31 of the eddy current brake 20. As is derived from the illustration according to Figure 2 The rotor 40 of the eddy current brake 20, which is configured with a plurality of slit-like configured channel openings 36, can be seen due to the laterally pushed ring-shaped closed element 24. The slit-like configured channel openings 36 represent the mouth positions of the flow channels 34 configured in the rotor 40 of the eddy current brake 20. The rotor 40 of the eddy current brake 20 is not visible in the illustration according to Figure 1 but is obscured by other structural elements due to the other components of the vehicle drive 8. The eddy current brake 20 itself is surrounded by the housing of the electric machine 18. It is furthermore derived from the illustration according to Figure 2 that, in the case of the open air feed 30, not only the slit-like configured channel openings 36 of the flow channels 34 are open, but also the closed cover 26 arranged centrally in the hub region 22 of the wheel 10 is moved out laterally according to the lateral offset 32, whereby a flow deflection 60 of the air flow 58, which will be described in more detail below, is achieved (see the illustration according to Figure 4

[0033] Similar to the illustration according to Figure 1 In the perspective view of the vehicle drive 8 according to Figure 2 with open air feed 30, the wheel outer side is designated by reference 66 and the wheel inner side, which faces a not more closely shown wheel house of the vehicle, is designated by reference 68.

[0034] The ring-shaped configured closed element 24 extends in the circumferential direction 38, as is indicated by the arrow on the wheel inner side 68 in Figure 2 Figure 1 ​​​​The position shown is in the case of closed air supply 28. Figure 2 The displacement movement of the position shown in the case of the open air supply 30 can be achieved, for example, by means of an electromechanical adjuster in a hydraulic manner or by means of one or more bimetallic springs. Using bimetallic springs advantageously enables actuation of the annular closure element 24 in response to a rise in temperature within the eddy current brake 20. Since, for example, at least one bimetallic spring used responds to a rise in temperature and a response limit can be predetermined by a corresponding alloy, the annular closure element 24 can be correspondingly actuated by at least one bimetallic spring when the temperature of the eddy current brake 20 rises, thereby enabling a transfer from the closed air supply 28 to... Figure 2 The open air supply 30 is shown.

[0035] according to Figure 3 The diagram shows that the vehicle drive 8 according to the present invention is at the height of the wheel axle. Figure 1 The cross-sectional view shown is in a state with the air supply 28 closed.

[0036] By following Figure 3 The diagram shows that the vehicle drive 8 is essentially surrounded by a rim 16 on which the aforementioned tire 14 is located, rolling on the ground, such as a lane, with its tread 12 not shown in more detail here. Figure 3 The vehicle drive unit 8, shown in a cross-sectional view, is essentially surrounded by a wheel rim 16. The wheel rim 16 is connected to the transmission unit 44 via a threaded member that can be inserted into an opening 46 for wheel threads. Similar to the housing of the motor 18, this transmission unit is designed according to… Figure 3 The cross-sectional view is shown only schematically. The housing of the motor 18 and the transmission mechanism unit 44 receive the journal of the rotor 40 of the eddy current brake 20.

[0037] Through the design of rotor 40, the surface area swept by airflow on the outer side of rotor 40 is maximized. The various flow channels 34 of rotor 40 are arranged in a blade-like manner and maximized in terms of their surface area, thereby enabling the efficient removal of heat stored in the material of eddy current brake 20. Figure 3 The diagram shows that, Figure 3 Internal air cannot flow in through the closed position 52 of the annular sealing element 24. More precisely, the annular sealing element 24 moves into its closed position 52 on its outer peripheral surface 31, thereby preventing external air from entering the eddy current brake 20. (In accordance with...) Figure 3 The diagram shows two excitation coils 64 of the eddy current brake 20, which are shown opposite each other.

[0038] By following Figure 3 Furthermore, the diagram shows that,Figure 3 With the closed air feed 28 shown in the diagram, the closure element 24 with the taper 48 is seated at the face of the rotor 40 of the eddy current brake 20. The closure cap 26 with its conically shaped circumferential face comes to rest in an abutment 50 with the complementary geometry of the end side of the rotor 40 of the eddy current brake 20. In the closed position 52 of the annular closure element 24, that is to say with the closed air feed 28, ambient air cannot flow from the outside into the rotor 40 of the eddy current brake 20. In the cooling state of the vehicle drive 8 according to Figure 3 the diagram, the closed air feed 28 is selected. In the cooling state of the vehicle drive 8 according to Figure 3 the diagram, the wheel outer side is marked with the position 66 and the wheel inner side is marked with the position 68. Instead of the tire 14 shown in Figure 4 the diagram, as a wheel 10 it is also possible to select a rail vehicle as a place of use of the vehicle drive 8 according to the application, which is preferably designed as a single-wheel drive 9.

[0039] From the diagram according to Figure 4 a sectional view of the vehicle drive 8 according to the application is derived, which extends in the height of the wheel axle and reflects the state with the open air feed 30.

[0040] From the diagram according to Figure 2 it is derived that the annular closure element 24 is displaced on the outer circumferential face 31 of the eddy current brake 20 by a lateral offset 32 corresponding to a displacement stroke 54. Since now the slit-like passage opening 36 of the flow passage 34, which opens into the outer circumferential face 31, is exposed, as has already been shown in the diagram according to Figure 4 an open air feed 30 is created. Now, ambient air can flow into the rotor 40 of the eddy current brake 20. Simultaneously with the displacement of the annular closure element 24 over the displacement stroke 54, corresponding to the lateral offset 32, the closure cap 26 is displaced outward. Thereby, it is moved away from the end side of the rotor 40 of the eddy current brake 20 and thus constitutes a passage formed in the radial direction. From the diagram according to Figure 4 it is derived that the inflowing air flow 58 from the outside undergoes a flow deflection 60 and flows via the mutually facing faces of the outwardly arranged closure cap 26 and the end side of the rotor 40 towards the wheel inner side 68, that is to say in the wheel house of the vehicle, which is not shown here in more detail.

[0041] From the diagram according to Figure 3 it is furthermore derived that, similar to the diagram according to Figures 1 to 4As shown in the diagram, the vehicle drive 8 is received in the hub region 22 of the wheel 10. The vehicle drive 8 includes a transmission unit 44, a motor 18, and an eddy current brake 20 having its components (i.e., a rotor 40, excitation coils 64 arranged circumferentially, shown exemplarily here, and a closing cover 26 that can be moved into and out of the rotor 40).

[0042] The rotor 40, flowing from the inside, is shaped as a continuous ring such that it creates eddies for braking in the region of the excitation coil 64, and its body provides the largest possible surface over which the airflow 58 passes and absorbs heat. Air is drawn in through slit-like channel openings 36 in the housing of the eddy brake 20 and exhausted from the rotor 40 at the inner side 68 of the wheel, and vice versa, depending on the direction of rotation of the wheel 10. The closing mechanism, in the form of a closing cover 26 or an annular closing element 24, can be actuated electromechanically, hydraulically, or by means of a bimetallic spring. This can be designed according to the rotor temperature. Possible solutions include closing or releasing only the inlet of the flow channel 34 in the rotor 40, or only closing or releasing its outlet. The cooling regulation of this design of the eddy brake 20 can also be integrated into the vehicle's central drive or into the drive and braking unit near the wheels, as previously described... Figure 5.1 As shown.

[0043] By following Figure 5.2 and Figure 5.1 The partially shown cross-sectional view reveals that, in an advantageous embodiment of the vehicle drive 8 according to the invention at wheel 10, the annular closure element 24 and the closure cover 26 can be represented as a single component. In this case, the annular closure element 24 shifts into the toroidal surface at its end facing away from the electric drive and forms the closure cover 26, which is centered at the journal-shaped protrusion at the journal 42 of the rotor 40. Figure 5.2 In the state shown, the annular closure element 24 is positioned such that the closure cover 26 is set into the journal 42 according to its push stroke 54 and forms a closed air supply 28.

[0044] On the contrary Figure 4 The diagram shows an integral component comprising an annular sealing element 24 and a sealing cover 26 on its guiding surface above the excitation coil 64, according to... ​ The push stroke 54 shown is used to push outwards. Therefore, the sealing cover 26 protrudes from the journal 42 of the rotor 40, thus forming a flow surface between the profile of the rotor 40 and the sealing cover 26, allowing the airflow 58 to pass through. In this case, the annular sealing element 24 and the sealing cover 26 coupled thereto occupy a position where the open air delivery 30 can be achieved.

[0045] The application is not limited to the vehicle category, for example passenger car, but can also be used in commercial vehicles or rail vehicles.

[0046] The application is not limited to the embodiments described herein and the aspects emphasized therein. Rather, various modifications can be made within the scope of the application as defined by the claims.

Claims

1. Vehicle drive (8) of a vehicle, which vehicle drive has an electric machine (18), a transmission unit (44) and an eddy current brake (20) integrated in a wheel hub region (22), characterized in that The eddy current brake (20) has a rotor (40) which can be released by means of a closure cap (26) by the passage of an air flow (58), which is assigned an annular closure element (24).

2. The vehicle drive (8) according to claim 1, characterized in that The rotor (40) of the eddy current brake (20) has a maximized surface with flow channels (34) shaped like leaves.

3. Vehicle drive (8) according to claims 1 and 2, characterized in that The flow channels (34) open into the outer circumference (31) of the rotor (40).

4. The vehicle drive (8) according to claims 1 to 3, characterized in that The flow channels (34) open into slit-shaped channel openings (36) of the outer circumferential surface (31).

5. The vehicle drive (8) according to claims 1 to 4, characterized in that An annular closure element (24) is received on the outer circumferential surface (31), which can be moved between a closed position (52) and an open position (56) perpendicular to the circumferential direction (38) of the outer circumferential surface.

6. The vehicle drive (8) according to claims 1 to 5, characterized in that The annular closure element (24) can be moved electromechanically, hydraulically or by means of at least one bimetallic spring.

7. The vehicle drive (8) according to claims 1 to 6, characterized in that The annular closure element (24) imparts a push travel (54) to a closure cap (26) which is substantially surrounded by the rotor (40), which is identical to the push travel (54) of the annular closure element (24) when actuated.

8. The vehicle drive (8) according to claims 1 to 7, characterized in that Actuation of the annular closure element (24) is dependent on the temperature of the rotor (40) of the eddy current brake (20).

9. The vehicle drive (8) according to claims 1 to 8, characterized in that The annular closure element (24) releases or closes the slit-shaped channel openings (36) of the flow channels (34) on the outlet side.

10. The vehicle drive (8) according to claims 1 to 9, characterized in that In the closed position (52) of the annular closure element (24), the closure cap (26) embodied with a taper (48) is in abutment (50) with the rotor (40) of the eddy current brake (20).

11. The vehicle drive (8) according to claims 1 to 10, characterized in that In the open position (56) of the annular closure element (24), the closure cap (26) embodied with a taper (48) is detached from the rotor (40) of the eddy current brake (20).

12. Use of the vehicle drive (8) according to any one of claims 1 to 11 in an electrically driven vehicle, a utility vehicle or a rail vehicle.

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