Vehicle drive for vehicle

Abstract

The invention relates to a vehicle drive (10), in particular a single-wheel drive (12) of a vehicle (70), the single-wheel drive (12) comprising an electric machine (22), a transmission unit (40) and a brake device (29), and the vehicle drive (10) being accommodated in an installation space of a wheel (14), in particular in a rim (16). The braking device (29) is designed as an eddy current brake (30), the rotor (28) of which is designed as a fan wheel (48). The invention further relates to the use of the vehicle drive (10) in passenger vehicles, commercial vehicles or rail vehicles.

Description

TECHNICAL FIELD

[0001] The invention relates to a vehicle drive, in particular a single-wheel drive of a vehicle, wherein the single-wheel drive comprises an electric machine, a transmission unit and a brake device, and the vehicle drive is accommodated in a structural space of a wheel, in particular in a wheel rim. Furthermore, the invention relates to the use of the vehicle drive in passenger cars, delivery vehicles, rail vehicles and the like. BACKGROUND

[0002] DE 10 257 617 A1 relates to an eddy current brake device having a stator with a plurality of poles. The stator can be fastened at a vehicle frame. Windings composed of conductors wound around each of the plurality of poles form electromagnets, wherein adjacent windings are electrically connected to one another. A drum for receiving a wheel-rim-unit is arranged rotatably on an axle. Eddy currents are generated between the drum and the stator due to a relative movement of the drum with respect to the stator, which slow down the rotation of the wheel-rim-unit.

[0003] CH 504320 A D2 relates to an eddy current brake having a stator carrying a coil and having a plurality of pole shoes of alternating polarity which alternately lap the coil from both sides in the circumferential direction of the coil, and a rotor having the shape of a drum which is open on one side only, the drum having ribs which extend at its end sides and in the circumferential direction thereof, and the rotor surrounds the stator leaving an air gap, so that the pole shoes which are embedded in the circumferential direction of the coil from the side facing away from the end side of the drum extend parallel to the end side of the drum at an angle, and the cross section of the end wall of the drum at the elongated pole shoes approximately corresponds to the cross section of the ring part of the drum.

[0004] DE 10 2013 221 561 A1 relates to an assembly for cooling a rotating eddy current brake of a rail vehicle, wherein the rotating eddy current brake has at least one rotor which is connected in a rotationally fixed manner to an axle of a rotating frame of the rail vehicle, and at least one stator which is arranged positionally fixed at the rotating frame, and at least one housing which can be arranged at the rotating frame and which surrounds the rotating eddy current brake. At the housing there are arranged at least one air inlet opening through which air can enter into the housing, and at least one air outlet opening through which air can escape from the housing.

[0005] DE 10 2023 211 893 A1 relates to a vehicle drive for a vehicle, which has a wheel, a transmission, an input shaft and an output shaft. The output shaft is coupled to the wheel in order to drive the wheel with an output rotational speed N2. Furthermore, a brake device and an electric motor are provided, wherein the brake device and the electric motor are coupled to or arranged on the input shaft and 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 thereby reduce the input rotational speed N1, wherein the transmission is designed to convert the input rotational speed N1 into the output rotational speed N2.

[0006] In electrically driven vehicles, hub drives can be used. The structure of the hub drive comprises an electric machine, a brake and a jointly used transmission arranged in the wheel. The brake can be configured as an eddy current brake, which is smaller than a conventional disc brake, for example, at the wheel of the vehicle and which can be implemented wear-free and maintenance-free. The kinetic energy released during braking is recovered in the electrically driven vehicle by the electric machine or converted into heat in the brake system. This heat can be released by friction or, as in the case of an eddy current brake, by eddy currents in a rotating brake disc (rotor). The thermal energy is usually output at the surroundings in order not to damage the surrounding components and to be able to absorb and convert the generated braking energy in subsequent braking processes. SUMMARY

[0007] According to the solution proposed according to the invention, a vehicle drive, in particular a single-wheel drive of a vehicle, is proposed, wherein the single-wheel drive comprises an electric machine, a transmission unit and a brake device, and the vehicle drive is received in the installation space of a wheel, in particular in the rim. The brake device is configured as an eddy current brake, the rotor of which is implemented as a fan wheel.

[0008] With this design of the rotor, an efficient dissipation of the heat generated in the components of the eddy current brake of the brake device can be achieved, and thus an impermissible temperature rise is avoided.

[0009] In an advantageous design of the vehicle drive proposed according to the invention, the rotor implemented as a fan wheel has flow channels, which are implemented with an increased surface in the rotor. If the rotor is advantageously made of a metal material, an optimal discharge of waste heat can be achieved by the increased surface. In an advantageous design of the vehicle drive proposed according to the invention, the coil carrier has an outer ring, in which there is a slit-like opening extending in the circumferential direction, which represents an air inlet into the flow channels.

[0010] In an advantageous embodiment of the vehicle drive according to the application, the rotor comprises rotor blades which define flow channels at the air outlet. The rotor blades at the air outlet side of the rotor can be configured, for example, in the form of a reinforcing structure.

[0011] In an advantageous embodiment of the vehicle drive according to the application, the brake device, in particular the eddy current brake, is arranged on the side facing away from the rim cover which is configured in a closed manner, in particular at the wheel inner side of the air through-flowing wheel house of the vehicle. Reliable circulation of the surrounding air is thereby ensured, in which the waste heat can be dissipated.

[0012] In an advantageous embodiment of the vehicle drive according to the application, the transmission mechanism unit coupled to the wheel is a speed-changing transmission mechanism having a transmission ratio i > 1. Thereby, a higher rotational speed of the components of the vehicle drive compared to the rotational speed of the wheel to be braked is achieved.

[0013] In an advantageous embodiment of the vehicle drive according to the application, the through-flow of the rotor designed as a fan wheel extends from the slit-like openings arranged in the coil carrier into the flow channels of the rotor embodied as a fan wheel.

[0014] In an advantageous embodiment of the vehicle drive according to the application, the brake device, in particular the eddy current brake, is designed in a radial structure such that the field winding arranged in the coil carrier forms a radial air gap with respect to the outer ring which extends continuously. Alternatively, there is the possibility of providing an axial air gap with a winding and a continuous ring at the rotor in the axial direction.

[0015] In an advantageous embodiment of the vehicle drive according to the application, the vehicle drive is embodied as a single-wheel drive, in particular as a hub drive. Such a design enables a compact and lightweight construction, in particular a space-saving arrangement of the vehicle drive according to the application.

[0016] In an advantageous embodiment of the vehicle drive according to the application, depending on the direction of rotation of the wheel, the air flow is drawn in through the slit-like openings in the coil carrier and is discharged from the rotor at the wheel inner side or vice versa.

[0017] Furthermore, the application relates to the use of the vehicle drive in a passenger car, a goods vehicle, a transport vehicle, a bus, a minibus, a two-wheeler, a three-wheeler, a multi-wheeler, a truck tractor, a military vehicle or a rail vehicle.

[0018] Advantages of the application.

[0019] By means of the solution according to the application, the temperature in a single-wheel drive can be reduced more quickly by targeted air guidance and higher rotational speed than with conventional disc brakes or drum brakes rotating at wheel speed. The increase in rotational speed is achieved by means of a transmission unit, in particular a planetary transmission, coupled in series with the eddy current brake and by means of targeted air guidance by the rotor of the fan wheel configured as an eddy current brake. Since it can be expected in the future that the wheel rim star will be closed in a feasible manner at the wheel, that is to say closed with a wheel cover or the like, in order to reduce the air resistance and thus the losses of the vehicle, an effective alternative for cooling a vehicle drive configured as a single-wheel drive can be provided by means of the solution according to the application. The targeted air guidance of the air flow and the higher rotational speed level as well as the installation of the eddy current brake on the wheel cover side of the air flow at the vehicle both make a not insignificant contribution to this.

[0020] In particular, cost advantages and loss advantages can be achieved by using components designed to be smaller and lighter. The configuration of the rotor of the fan wheel as an eddy current brake can significantly improve the surface available for cooling and its throughflow and thus the cooling effect. The surrounding air can be guided from the inside outwards or from the outside inwards depending on the direction of rotation and orientation of the rotor blades of the fan wheel when the drive shaft is rotating. The air flow thus flows through the coil carrier and the rotor configured as a fan wheel. The continuous outer ring is braked and heated in the braking case by the interaction with the field winding arranged radially relative thereto and the entire rotor configured as a fan wheel from a metal material can be cooled very efficiently by targeted air guidance as described above.

[0021] It goes without saying that the vehicle drive according to the application can not only be configured in its radial arrangement of components, but for example also comprise a continuous ring oriented axially at the rotor and field windings or permanent magnets oriented in the axial direction. Both implementation variants are feasible. BRIEF DESCRIPTION OF DRAWINGS

[0022] The embodiments of the application are explained in more detail according to the drawings and the following description.

[0023] in which: Figure 1 a perspective view of a vehicle drive according to the application is shown, in particular configured as a single wheel, and Figure 2 a cross-sectional view of a wheel and a vehicle drive received in the wheel is shown in perspective. Figure 1 in which: DETAILED DESCRIPTION

[0024] In the following description of embodiments of the application, identical or similar elements are denoted by the same reference signs, wherein, in individual cases, repeated description of these elements is omitted. The drawings show the subject matter of the application only schematically.

[0025] Figure 1 A vehicle drive 10 is shown, which is configured here, for example, as a single-wheel drive 12. The single-wheel drive comprises a wheel 14, the rim 16 of which receives a tire 18, at which a tread 20 is configured. Inside the rim 16, an electric machine 22 is arranged, which comprises a housing 24. The electric machine 22 comprises a drive shaft 26, which is coupled with a transmission unit 40 (see cross-sectional view according to Figure 2 .

[0026] The single-wheel drive 12 furthermore comprises a brake device 29, which is configured here as an eddy current brake 30. As can be recognized in the perspective view according to Figure 1 , the rotor 28 of the brake device is embodied in the structural manner of a fan wheel 48, with rotor blades 52 arranged distributed along a circumferential direction 56. The rotor 28 of the brake device 29 is surrounded by a coil carrier 32 extending along the circumferential direction, in which a plurality of field coils are arranged, which are, however, obscured in Figure 1 by the coil carrier 32 extending along the circumferential direction 56. According to the perspective view of the vehicle drive 10 according to Figure 1 , a plurality of slit-like openings 58 arranged next to one another along the circumferential direction 56 are arranged between the coil carrier 32 and the continuously extending outer ring 50. According to the throughflow direction of the air flow 64 (see view according to Figure 2 , the openings represent air inlets 36 or air outlets 38. The rotor blades 52, which are configured in the form of a reinforcing structure 54, extend beyond the outer ring 50, which means that the continuously embodied outer ring 50 does not extend over the entire axial length of the rotor blades 52. It is derived from the view according to Figure 1 , that, in addition to the electric machine 22 and the transmission, which is configured as a planetary transmission, i.e. the mentioned transmission unit 40, the vehicle drive 10 also comprises Figure 1 field coils, which are obscured by the coil carrier 32. The brake device 29, which is configured as an eddy current brake 30, comprises the mentioned rotor 28, the coil carrier 32 and the field coils arranged in the coil carrier. The braking action of the electromagnet, which is configured here as a field coil, can also be realized by a permanent magnet. According to Figure 1In the diagram in Fig. 1, the wheel rotational speed of the wheel 14 is guided by means of the transmission unit 40 and the drive shaft 26 to the electric machine 22 and to the brake device 29 configured as the eddy current brake 30. Thereby, a higher rotational speed is obtained at these components compared to the rotational speed of the wheel 14 and a smaller torque acting on the drive and the brake in the case of a transmission ratio i > 1. Thereby, the brake device 29 configured as the eddy current brake 30 can be designed to be smaller.

[0027] The vehicle drive 10 designed as a single-wheel drive 12 according to the application is distinguished in that the rotor 28 of the eddy current brake 30 configured as the brake device 29 is an internally through-flowing rotor 28 which is shaped in such a way that the rotor configures the eddy currents for braking in the region of the field coil 34 and acts as a fan wheel 48 with as large a surface as possible at the rest of the body. Here, depending on the direction of rotation of the wheel 14, the ambient air is drawn in through the slit-like openings 58 between the coil carrier 32 and the continuous outer ring 50 and is discharged from the rotor 28 at the wheel inner side (see position 46 in Fig. 1) or vice versa. Figure 2

[0028] From the sectional view according to Fig. 2, it can be derived that the wheel 14 shown in section is closed at its wheel outer side 44 by means of the rim cap 42. By mounting the rim cap 42 at the wheel outer side 44 of the wheel 14, i.e. at the rim 16, a continuous surface is formed which avoids eddy currents and improves the air resistance, in particular the air resistance coefficient (CW value) of the wheel 14. Figure 2 It is furthermore shown that the air flow 64 enters into the flow channel 60 of the rotor 28 configured as the fan wheel 48, for example through the slit-like openings 58 arranged between the continuous outer ring 50 on the one hand and the coil carrier 32 on the other hand as air inlets 36. In order to improve the heat dissipation of the heated rotor 28 configured as the fan wheel 48 of the brake device 29 configured as the eddy current brake 30, an efficient heat dissipation can be achieved, i.e. a temperature reduction due to the through-flow of the flow channel 60 by the air flow 64. The air flow is diverted in such a way that the air flow 64 escapes on the wheel inner side 46 of the wheel housing 68 of the vehicle 70 after passing the diverting portion 66. Figure 2

[0029] From the diagram according to Fig. 3, it can be derived that a plurality of field coils 34 are arranged opposite to each other in the interior of the coil carrier 32. Instead of the field coils 34, permanent magnets can also be arranged next to each other in the circumferential direction 56 along the circumference of the coil carrier 32, which are opposite to the outer circumference of the rotor 28 configured as the fan wheel 48 of the brake device 29 configured as the eddy current brake 30 with a configured air gap. Figure 2

[0030] ​​​A radial air gap extends between the field coil 34 and the continuous outer ring 50. This radial air gap should be minimized as far as possible, however, can be designed as small as possible due to the speed difference between the rotating rotor 28 on the one hand and the stationary field coil 34 on the other hand. In addition to the radial arrangement as shown in Figure 2 In principle, an axial arrangement is also possible, that is to say, not only the axial orientation of the continuous outer ring 50, but also of the field coil 34, represents a practical variant.

[0031] The increased surface of the flow channel 60 of the rotor 28 configured as a fan wheel 48 is denoted by reference numeral 62. The larger the increased surface 62 of the rotor 28 configured as a fan wheel 48 can be designed, the more efficient the heat dissipation can be achieved when the rotor 28 is traversed by the mentioned air flow 64.

[0032] As already set out above, by configuring the transmission unit 40 as a planetary transmission, in particular as a variable-speed transmission, it is possible to increase the rotational speed of the rotor 28 of the electric machine 22 in accordance with the transmission ratio (i > 1) of the transmission unit 40 configured as a planetary transmission. Thereby, a higher rotational speed is obtained compared to the rotational speed present at the wheel 14 and a smaller torque can be braked by the brake device 29 configured as an eddy current brake 30. Thereby, the brake device 29 designed as an eddy current brake 30 can be designed significantly smaller.

[0033] The eddy current brake 30 as designed in Figure 1 and Figure 2 can also be integrated in a central drive or in a drive and brake unit close to the wheel. It is to be noted that a sufficient air supply to the brake device 29 configured as an eddy current brake 30 for its heat dissipation.

[0034] Furthermore, the invention relates to the use of a vehicle drive 10 as described above according to Figure 1 and Figure 2 in particular configured as a single-wheel drive 12 in a passenger car, a delivery van, a transport vehicle, a bus, a minibus, a two-wheeler, a three-wheeler, a multi-wheeler, a truck tractor, a military vehicle or a rail vehicle.

[0035] The invention is not limited to the embodiments and aspects emphasized therein described herein. Rather, various variants can be realized within the framework of the practice of the person skilled in the art within the scope specified by the claims.

Claims

1. A vehicle drive (10), in particular single-wheel drive (12) of a vehicle (70), wherein The single-wheel drive (12) comprises an electric machine (22), a transmission unit (40) and a brake device (29) and is received in the structural space of a wheel (14), in particular in a rim (16), characterized in that the brake device (29) is configured as an eddy current brake (30) whose rotor (28) is embodied as a fan wheel (48).

2. The vehicle drive (10) according to claim 1, characterized in that The rotor (28), embodied as a fan wheel (48), has flow channels (60) which are embodied with enlarged surfaces (62) in the rotor (28).

3. The vehicle drive (10) according to claims 1 to 2, characterized in that The rotor (28) has an outer ring (50), in particular a continuously embodied outer ring (50), along which a slit-like opening (58) extends in the circumferential direction (56), which slit-like opening represents an air inlet (36) into the flow channels (60).

4. The vehicle drive (10) according to claims 1 to 3, characterized in that The rotor (28) has rotor blades (52) which delimit flow channels (60) at air outlets (38).

5. The vehicle drive (10) according to claims 1 to 4, characterized in that The rotor blades (52) are configured in the form of a reinforcement structure (54).

6. The vehicle drive (10) according to claims 1 to 5, characterized in that The brake device (29), in particular the eddy current brake (30), is arranged on the side facing away from the rim cover (42), in particular on the wheel inner side (46) of an air throughflowing wheel cover (68) of the vehicle (70).

7. The vehicle drive (10) according to claims 1 to 6, characterized in that The transmission unit (40) coupled with the wheel (14) is a variable transmission having a transmission ratio i > 1.

8. The vehicle drive (10) according to claims 1 to 7, characterized in that The throughflow of the rotor (28) designed as a fan wheel (48) extends from the slit-like opening (58) arranged in the coil carrier (32) into the flow channels (60) of the rotor (28) embodied as a fan wheel (48).

9. The vehicle drive (10) according to claims 1 to 8, characterized in that The brake device (29), in particular the eddy current brake (30), is designed in a radial structure such that the field winding (34) arranged in the coil carrier (32) forms a radial air gap with respect to the continuous outer ring (50).

10. The vehicle drive (10) according to claims 1 to 9, characterized in that The vehicle drive (10) is embodied as a single-wheel drive (12), in particular as a hub drive.

11. The vehicle drive (10) according to claims 1 to 10, characterized in that Depending on the direction of rotation of the wheel (14), the air flow (64) is drawn in through the slit-like opening (58) in the coil carrier (32) and is discharged from the rotor (28) on the wheel inner side (46) or vice versa.

12. Use of a vehicle drive (10) according to any one of claims 1 to 11 in a passenger car, a delivery van, a transport vehicle, a bus, a minibus, a two-wheeler, a three-wheeler, a multi-wheeler, a truck tractor, a military vehicle or a rail vehicle.

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