Vehicle drive for a vehicle

Abstract

Proposed is a vehicle drive (100) for a vehicle, comprising a wheel (10), a transmission (12) with an input shaft (14) and an output shaft (16), wherein the output shaft (16) is coupled to the wheel (10) in order to drive the wheel (10) at an output speed (n2), a braking device (18), and an electric motor (20), wherein the braking device (18) and the electric motor (20) are coupled to the input shaft (14) or arranged on the input shaft (14), wherein the electric motor (20) is designed to drive the input shaft (14) at an input speed (n1), wherein the braking device (18) is designed to brake the input shaft (14) in order to reduce the input speed (n1), wherein the transmission (12) is designed to translate the input speed (n1) into the output speed (n2).

Description

The invention relates to a vehicle drive for a vehicle and to a vehicle having such a vehicle drive.Prior ArtThe increasing spread of single wheel electric drives in modern vehicles has fundamentally changed the automobile industry in recent years. Vehicles such as the Mercedes eSLS, Rimac, and Tesla have shown that single wheel drives provide an efficient and powerful way to design the mobility of the future. Furthermore, recent developments in the industry have enabled the introduction of single wheel drives directly in the wheel itself, as is the case with vehicles such as Lightyear, Lordstown and Hyundai. These innovative systems offer numerous advantages, including improved energy efficiency and performance.A common feature of single wheel drives is the use of a gear ratio to transmit torque to the single wheel. However, some manufacturers, such as Lordstown and Lightyear, have already set direct drives without transmissions to realize even more efficient drive systems. Despite these technological advances, the brake systems in conventional passenger cars (cars) are still complicated and inaccurate. The brake systems are usually connected to the driven wheel in a fixed manner with respect to speed and require high braking torques in order to bring the vehicles securely to a standstill. This results in large and heavy braking systems, whether in the form of drum or disc brakes.In the prior art, the individual wheel drives are often combined with a brake which is usually designed as a disc brake with friction linings. These brakes are usually large, difficult and inaccurate to actuate, since they must apply the high wheel torques by means of friction linings which are subject to fluctuations in the coefficient of friction. The brakes cause abrasion during the braking process and therefore fine dust and wear. Moreover, controllability of the brake is complex, since friction values of the brake pads may vary as a result of aging and / or operating mode. An exact assignment of a clamping force at the brake and / or a braking torque is therefore often difficult and possibly subject to errors.A weight saving and a better adjustability of the braking torques would thus be advantageous in principle. Particularly in the case of drives in the wheel, the reduction in the overall size of the brakes is also preferred. Another object is to avoid abrasion and, as a result, to reduce maintenance requirements and particulate matter emission.Exemplary vehicle drives are known in each case from DE 10 2009 006 196 A1, DE 69 913 281 T2 or DE 10 2018 106 479 A1.The object of the invention is thus to provide an improved vehicle drive.The object is achieved by a vehicle drive according to the features of claim 1.Disclosure of the InventionAccording to a first aspect, a vehicle drive for a vehicle is proposed. The vehicle drive has a wheel, a transmission with an input shaft and an output shaft. The output shaft is coupled to the wheel to drive the wheel at an output speed. The vehicle drive has a braking device and an electric motor. The brake device and the electric motor are coupled to the input shaft or are arranged on the input shaft. The electric motor is designed to drive the input shaft at an input rotational speed. The brake device is configured to brake the input shaft so as to reduce the input rotational speed. The transmission is configured to translate the input speed into the output speed.Vehicle propulsion describes a system that serves to propel a vehicle and allow it to move. The at least one wheel denotes a rotatable member used to propel the vehicle. The wheel can preferably have a rim and a tire covering. The transmission describes a mechanical system having an input shaft and an output shaft.It enables the change of the speed and the torque between input and output. The input shaft describes a shaft or a rotatable shaft body which is part of the transmission or can be coupled to the transmission in a motion-transmitting manner and serves as an input for a driving force or a driving torque. The output shaft describes a shaft or a rotatable shaft body which is part of the transmission or can be coupled to the transmission in a motion-transmitting manner and provides an output force or an output torque. The coupling with the wheel takes place directly or indirectly by means of the output shaft.The output shaft is preferably connected or coupled to the wheel to drive the wheel at a particular speed. The coupling can be effected with at least one further part being interposed. The braking device describes a system or mechanism used to slow or stop movement of the input shaft and, via the transmission, also that of the output shaft. The electric motor describes a device or a system which converts / converts electrical energy into mechanical energy and is used to drive the input shaft. The coupling to the input shaft is preferably effected directly or indirectly.The brake device and the electric motor are either directly connected to the input shaft or mounted on the input shaft in order to influence the movement thereof. The electric motor is preferably designed to drive the input shaft at a specific input speed. To provide a brake device function, the brake device is constructed and arranged to slow or stop movement of the input shaft, which reduces the input speed.To provide a transmission gear function, the transmission has the ability to translate the input speed to an output speed, whereby the speed and torque of the wheel can be controlled.The present invention is concerned with utilizing the transmission, in particular a reduction gear of the vehicle drive, also for the brake device. As a result, the rotational speed of the brake is raised to a higher level and, in turn, a braking torque request is reduced. This allows a smaller, lighter construction in conventional brakes (e.g. in the case of a drum brake or disc brake) or allows new braking technologies to be introduced (e.g. a multi-disc brake, a low-wear and dust-free wet multi-disc brake, a wear-free and dust-free eddy current brake).It is particularly advantageous here that a smaller structural size and a smaller weight can be achieved. In addition, a wear-reduced brake, which is possibly maintenance-free over the service life, can be achieved. Furthermore, a reduction or avoidance of particulate matter emissions can be achieved. The possibility of integrating the electric motor and the brake in a vehicle drive, in particular designed as a drive module, is likewise provided.According to one embodiment, the brake device is arranged between the transmission and the electric motor. Alternatively, the electric motor is arranged between the transmission and the brake device.The arrangement of the brake device and of the electric motor can thus also be interchanged. The described embodiment thus preferably relates to an operating sequence rather than to a structural arrangement of the components. This makes it possible, for example, to use a wear-free and dust-free eddy current brake, in particular an exactly adjustable eddy current brake.According to one embodiment, the transmission comprises a planetary transmission or a stepped planetary transmission or a spur gear transmission.A planetary gear preferably describes a type of gear mechanism which has a central sun gear, planetary gears and an annular gear. It allows for various gear ratios and is used in automatic transmissions and other applications. A stepped planetary gear preferably describes a special variant of the planetary gear, in which the planetary gears are arranged in steps in order to achieve a larger transmission ratio. A spur gear transmission describes a transmission in which the power transmission is effected by spur gears which are in engagement with one another. Possible and purely exemplary transmission ratios i can vary between 3 and 15.According to one embodiment, the brake device has a friction brake, in particular a drum brake, or a disc brake, or a multi-disc brake, or an in particular encapsulated, preferably dust-free brake, in particular an eddy current brake or a wet multi-disc brake.A friction brake preferably describes a brake in which the deceleration is generated by friction between two surfaces. It can occur in various embodiments. A drum brake preferably describes a specific type of friction brake in which the brake pads are enclosed in a drum and are pressed against the drum when needed to slow movement. A disc brake preferably describes a brake in which the deceleration is generated by friction between brake pads and a rotating brake disc. It is often found in modern vehicles. A multi-disk brake preferably describes a brake in which brake pads or disks are used to slow movement. It may occur in various configurations. A sealed brake preferably describes a brake that is particularly protected from dust and dirt to increase the life and efficiency of the brake.A dust-free brake preferably describes a brake which is designed to generate or pick up as little dust as possible in order to improve cleanliness and serviceability. An eddy current brake preferably describes a specific type of brake in which eddy currents are generated to convert momentum to heat and slow motion. A wet multi-disk brake preferably describes a brake in which the brake pads and / or disks operate in an oil bath to reduce friction and increase durability.The eddy current brake preferably has an electrically conductive disk or drum with electromagnets arranged next to it. The electromagnets can be arranged in such a way that an axial or radial air gap results. Variation is possible with respect to an arrangement and / or a number of the electromagnets. For example, electromagnets can be arranged on both sides of the disk and can each be separated from the disk by an axial air gap.The eddy current brake enables a precise adjustability of the braking torque. Furthermore, the use of brake fluid can be dispensed with. In addition, there is a higher degree of freedom in product design, since the accessibility of the brake does not have to be taken into account for the case of maintenance.According to one embodiment, the electric motor comprises a permanent-excited synchronous motor, PSM, or an asynchronous motor, ASM, or an electrically excited synchronous motor, ESM.A permanent magnet synchronous motor (PSM) is a synchronous motor in which the excitation of the rotor is effected by permanent magnets. This type of motor is known for high efficiency and high power density. An asynchronous motor (ASM) is a motor in which the rotor does not run synchronously with the rotating magnetic field of the stator. This is also known as an induction motor and is widely used in various applications due to its simple construction and maintenance. An electrically excited synchronous motor (ESM) is a synchronous motor in which the rotor is excited by electric field windings rather than permanent magnets. This enables more accurate control of engine performance.The term "electric motor" can also be replaced in the present case by the term "electric machine", in particular if the electric motor can operate not only by motor but also in generator form. If the electric motor is designed, for example, for brake energy recuperation, it is an electric machine which can be operated by motor and generator.According to one embodiment, the transmission has a planetary transmission, in particular a stepped planetary transmission, and the brake device has an eddy current brake having a rotor and a stator. The electric motor has a rotor and a stator, wherein the rotor of the eddy current brake is formed integrally with the rotor of the electric motor, or wherein the stator of the eddy current brake is formed integrally with the stator of the electric motor.The eddy current brake describes a specific type of brake in the present case, in which eddy currents are generated in order to convert kinetic energy into heat and to slow the movement. It comprises a rotor and a stator. The electric motor describes a device that converts electrical energy into mechanical movement in order to drive a shaft, in the present case the input shaft. It comprises a rotor and a stator.The rotor is preferably a portion of the electric motor and / or eddy current brake that rotates and helps to generate or slow the motion. The stator is preferably a stationary part of the electric motor and / or the eddy current brake, which generates or influences the magnetic field acting on the rotor. The special feature is that the rotor of the eddy current brake is either formed integrally with the rotor of the electric motor or the stator of the eddy current brake is formed integrally with the stator of the electric motor. This can affect the integration and efficiency of the system.In other words, a transmission between the eddy current brake and the electric motor is not required and can be saved. It is particularly preferred to use a planetary gear mechanism optimized for installation space. Due to the omission of the transmission between the eddy current brake and the electric motor, the rotor of the electric motor and the rotor of the eddy current brake could be embodied in one piece. Alternatively, the stators of the eddy current brake and of the electric motor can be combined. This results in advantages and synergies with regard to electrical contacting and / or cooling of the stators, since, among other things, common plugs and / or a common cooling circuit can be used.According to one embodiment, the eddy current brake has an axially or radially arranged air gap.The axially arranged air gap preferably describes an air gap, the air gap height of which is measured parallel to the axis of rotation. An axially disposed air gap may be used to configure the eddy current brake to act in the axial direction. A radially arranged air gap preferably describes an air gap, the air gap height of which is measured perpendicular to the axis of rotation, i.e. in the radial direction. A radially disposed air gap may be used to configure the eddy current brake to act in the radial direction. The choice between these two arrangements can affect the functioning and applicability of the eddy current brake in various situations.According to one embodiment, the transmission and / or the brake device and / or the electric motor are arranged in an installation space provided in the wheel.The installation space preferably describes a space or a specific zone within the wheel, for example provided in an inner region of a rim which is provided for accommodating the above-mentioned components (transmission, brake device, electric motor). The embodiment describes that in the embodiment described, at least one of the components mentioned (transmission and / or brake device and / or electric motor) is arranged in a construction space provided specifically in the wheel.This means that these components are accommodated within the wheel, in particular in the wheel rim, which makes space-saving and makes integration into the vehicle easier. This may be useful in various vehicle applications to save space or reduce the weight of the propulsion system. In other words, according to this embodiment, integration of at least one of the components (transmission and / or brake device and / or electric motor) in the rim of the wheel is possible.Particularly preferably, the entire unit (transmission and brake device and electric motor) is therefore not arranged within the vehicle body, i.e. the sprung mass, but rather in a region or installation space within the rim of the wheel, i.e. within the unsprung mass.In the present case, a vehicle having at least one such vehicle drive is also proposed.Furthermore, a vehicle having at least one such vehicle drive is proposed, wherein the vehicle has a vehicle body, wherein the transmission, the braking device and the electric motor are arranged on or in the vehicle body, and wherein the wheel is coupled to the output shaft by means of a articulated shaft.The vehicle body preferably describes an exterior structure or frame of the vehicle that protects and / or receives passengers, cargo, and other components and forms and / or affects the exterior appearance of the vehicle. The vehicle body also provides a support structure of the vehicle. The propeller shaft describes a shaft used to transmit rotational motion from one source to another via a link. The embodiment relates to at least one such vehicle drive being present in a vehicle. In this vehicle, the transmission, the brake device and the electric motor are arranged on or in the vehicle body.The wheel is coupled to the output shaft of the drive via a propeller shaft, which means that the driving force from the drive system is transmitted to the wheel to drive the vehicle. This arrangement can be used in various types of vehicles in order to integrate the drive components efficiently and in a space-saving manner.The vehicle can be a commercial vehicle, for example a delivery vehicle, a passenger vehicle, a transport vehicle, a bus, a truck, a small bus, a two-wheel vehicle, a three-wheel vehicle, a multi-wheel vehicle, a military vehicle, a truck tractor or the like. In general, the vehicle describes a means of transport which serves for transporting people and / or goods.The explanations made for the vehicle drive apply accordingly to a vehicle with such a vehicle drive. It is understood that linguistic modifications of features can be transformed for the vehicle according to common language practice without such formulations having to be explicitly listed here.The described embodiments and developments can be combined with one another as desired.Further possible embodiments, developments and implementations of the invention also include combinations of features of the invention described above or below with respect to the exemplary embodiments, which combinations are not explicitly mentioned.Brief Description of the DrawingsThe accompanying drawings are intended to provide a further understanding of the embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention.Other embodiments and many of the advantages mentioned are evident with reference to the drawings. The elements of the drawings shown are not necessarily shown true to scale with respect to one another.The following are shown: FIG. 1 schematically shows a vehicle having an exemplary embodiment of a vehicle drive; FIG. 2 schematically shows an exemplary embodiment of a vehicle drive; FIG. 3 schematically shows an exemplary embodiment of a vehicle drive; FIG. 4 schematically shows an exemplary embodiment of a vehicle drive; FIG. 5 schematically shows an exemplary embodiment of a vehicle drive; and FIG. 6 schematically shows an exemplary embodiment of a vehicle drive.In the figures of the drawings, identical reference numerals designate identical or functionally identical elements, components or components, unless indicated to the contrary.FIG. 1 schematically shows a vehicle 1000 having an exemplary embodiment of at least one vehicle drive 100. The vehicle 1000 comprises in the present case two vehicle drives 100, which can be seen in FIGS. 2 to 6 in several exemplary embodiments. The vehicle 1000 includes a vehicle body 1002.FIG. 2 schematically shows an exemplary embodiment of the vehicle drive 100. The vehicle drive 100 has a wheel 10 and a transmission 12. The transmission 12 includes at least one input shaft 14 and an output shaft 16. The output shaft 16 is coupled to the wheel to drive the wheel 10 at an output speed n2. The vehicle drive 100 further comprises a brake device 18 and an electric motor 20. The brake device 18 and the electric motor 20 are coupled to the at least one input shaft 14 or are arranged on the at least one input shaft 14.In some embodiments, the input shaft 14 can be formed in one piece or in one piece or in multiple pieces. For example, the brake device 18 can have an input shaft part and the electric motor 20 can have an input shaft part. The electric motor 20 is designed to drive the at least one input shaft 14 at an input rotational speed n1. The brake device 18 is configured to brake the at least one input shaft 14 in order to reduce the input rotational speed n 1. The transmission 12 is configured to translate the input rotational speed n 1 into the output rotational speed n 2, preferably according to a transmission ratio i.In principle, the brake device 18 can be arranged between the transmission 12 and the electric motor 20 (see FIGS. 2 to 4 and 6 ). Alternatively, the electric motor 20 may be disposed between the transmission 12 and the brake device 18 (see FIG. 5 ).The transmission 12 can basically be designed as a planetary transmission or a stepped planetary transmission or a spur gear transmission.The brake device 18 can basically be designed as a friction brake, in particular a drum brake, or a disc brake, or a multi-disc brake, or an in particular encapsulated, preferably dust-free brake, in particular an eddy current brake or a wet multi-disc brake.The electric motor 20 can be of any type, preferably a permanently excited synchronous motor, PSM, or as an asynchronous motor, ASM, or as an electrically excited synchronous motor, ESM.FIG. 3 schematically shows a further exemplary embodiment of the vehicle drive 100. According to FIG. 3, the transmission 12, the brake device 18 and the electric motor 20 are arranged in an installation space 22 provided in the wheel 10. The space 22 may be provided in a rim 24 of the wheel 10.Alternatively, the transmission 12, the brake device 18, and the electric motor 20 may be disposed on the vehicle body 1002. The wheel 10 may be coupled to the output shaft 16 by means of a propeller shaft 26 (see left-hand embodiment of the vehicle drive 100 in FIG. 1 ).FIG. 4 schematically shows a further exemplary embodiment of the vehicle drive 100. According to FIG. 4, the transmission 12, the brake device 18 and the electric motor 20 are arranged in the installation space 22 provided in the wheel 10. The transmission 12 is a planetary transmission, in particular a stepped planetary transmission. The brake device 18 is an eddy current brake 28 having a rotor 30 designed in the form of a brake disk and a stator 32 designed in the form of electromagnets. The electric motor 20 comprises a rotor 34 and a stator 36 (see FIG. 6 ). According to FIG. 4, the eddy current brake 28 has an axially arranged air gap 38.FIG. 5 schematically shows a further exemplary embodiment of the vehicle drive 100. According to FIG. 4, the transmission 12, the brake device 18 and the electric motor 20 are arranged in the installation space 22 provided in the wheel 10. The electric motor 20 is arranged between the transmission 12 and the brake device 18. The transmission 12 is a planetary transmission, in particular a stepped planetary transmission. According to FIG. 5, the eddy current brake 28 has a radially arranged air gap 40 between the rotor 30 and the stator 32.FIG. 6 schematically shows a further exemplary embodiment of the vehicle drive 100. According to FIG. 6, the transmission 12, the brake device 18 and the electric motor 20 are arranged in the installation space 22 provided in the wheel 10. The brake device 18 is arranged between the electric motor 20 and the transmission 12. The transmission 12 is a planetary transmission, in particular a stepped planetary transmission. According to FIG. 6, the eddy current brake 28 has the radially arranged air gap 40 between the rotor 30 and the stator 32. The stator 32 of the eddy current brake 28 is formed integrally with the stator 36 of the electric motor 20.Alternatively, it is also conceivable for the rotor 30 of the eddy current brake 28 to be formed integrally with the rotor 34 of the electric motor 20 (not shown).Alternatively, parts of the drive can also be mounted in the wheel, further parts can be mounted on the vehicle body and connected by a pivot shaft (not shown)References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2009 006 196 A1

[0006] DE 69 913 281 T2

[0006] DE 10 2018 106 479 A1

[0006]

Claims

Vehicle drive (100) for a vehicle (1000), comprising - a wheel (10), - a transmission (12) having an input shaft (14) and an output shaft (16), wherein the output shaft (16) is coupled to the wheel (10) in order to drive the wheel (10) at an output rotational speed (n2), - a braking device (18), and - an electric motor (20), wherein the braking device (18) and the electric motor (20) are coupled to the input shaft (14) or are arranged on the input shaft (14), wherein the electric motor (20) is configured to drive the input shaft (14) at an input rotational speed (n1), wherein the braking device (18) is configured to brake the input shaft (14) in order to thus reduce the input rotational speed (n1), wherein the transmission (12) is configured to, the input rotational speed (n1) is converted into the output rotational speed (n2).Vehicle drive according to Claim 1, wherein the braking device (18) is arranged between the transmission (12) and the electric motor (20), or wherein the electric motor (20) is arranged between the transmission (12) and the braking device (18).Vehicle drive according to Claim 1 or 2, wherein the transmission (12) has a planetary transmission or a stepped planetary transmission or a spur gear transmission.Vehicle drive according to one of the preceding claims, wherein the brake device (18) has a friction brake, in particular a drum brake, or a disc brake, or a multi-disc brake, or an in particular encapsulated, preferably dust-free brake, in particular an eddy current brake or a wet multi-disc brake.Vehicle drive according to one of the preceding claims, wherein the electric motor (20) has a permanently excited synchronous motor, PSM, or an asynchronous motor, ASM, or an electrically excited synchronous motor, ESM.Vehicle drive according to either of Claims 1 and 2, wherein the transmission (12) has a planetary transmission, in particular a stepped planetary transmission, and the braking device (18) has an eddy current brake (28) having a rotor (30) and a stator (32), wherein the electric motor (20) has a rotor (34) and a stator (36), wherein the rotor (30) of the eddy current brake (28) is formed integrally with the rotor (34) of the electric motor (20), or wherein the stator (32) of the eddy current brake (28) is formed integrally with the stator (36) of the electric motor (20).Vehicle drive according to Claim 4 or 6, wherein the eddy current brake (28) has an axially arranged air gap (38) or a radially arranged air gap (40).The vehicle drive of claim 7, wherein an air gap height of the axially disposed air gap extends parallel to the axis of rotation, and wherein an air gap height of the radially disposed air gap extends perpendicular to the axis of rotation.Vehicle drive according to one of the preceding claims, wherein the transmission (12) and / or the brake device (18) and / or the electric motor (20) are arranged in an installation space (22) provided in the wheel (10), in particular in a rim (24) of the wheel.Vehicle drive according to one of Claims 1 to 8, wherein the transmission (12), the braking device (18) and the electric motor (20) are arranged on a vehicle body (1002), and wherein the wheel (10) is coupled to the output shaft (16) by means of a articulated shaft (26).

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