Steer-by-Wire-Lenkvorrichtung

Abstract

Steer-by-wire steering device with at least one steering handle (10a) and with at least one steering function unit (12a; 12b) which is provided at least for generating a steering resistance and / or a restoring torque on the steering handle (10a), characterized in that the steering function unit (12a; 12b) comprises at least one rack and pinion drive (14a; 14b).

Description

Prior ArtThe invention is based on a steer-by-wire steering device according to the preamble of claim 1.Vehicles with steer-by-wire steering systems are known from the prior art, which manage without a direct mechanical connection between a steering handle and steered vehicle wheels and in which a steering command is exclusively forwarded electrically to the steering handle. Due to the lack of a mechanical connection, all safety-relevant components of the steering system must be designed redundant in order to ensure steerability of the vehicle even in the event of a fault. In particular, it must be ensured at any time that steering angle information is forwarded from a steering handle to a wheel steering angle actuator and / or a steering gear. In addition, it must be ensured that the steering handle does not move in an uncontrolled manner due to a lack of steering resistance and / or restoring torque. In addition, it is advantageous if the driver also receives feedback from the road and from the vehicle wheels in the event of a fault.A steer-by-wire steering device of the generic type having a steering function unit which comprises a rack and pinion gear is known from DE 42 07 719 A1.Furthermore, conventional mechanical steering devices for motor vehicles are disclosed in DE 10 2007 027 039 B4 and WO 2003 / 053 764 A1.The object of the invention is in particular to provide a steer-by-wire steering device with improved properties with regard to operational safety. The object is achieved by a steer-by-wire steering device having the features of claim 1 and by a steering system having the features of claim 10, while advantageous embodiments and developments of the invention can be gathered from the dependent claims.Disclosure of the InventionThe invention is based on a steer-by-wire steering device having at least one steering handle and having at least one steering function unit which is provided at least for generating a steering resistance and / or a restoring torque on the steering handle.It is proposed that the steering function unit, in particular at least for generating the steering resistance, comprises at least one rack and pinion gear. The rack and pinion gear has at least one rack and advantageously at least one gear and / or drive pinion coupled to the rack. This configuration can increase operational reliability in particular. In particular, the rack and pinion gear can avoid uncontrolled movement of the steering handle because of its inherent high friction, whereby an efficiency, in particular an effective efficiency, a component efficiency, an installation space efficiency and / or a cost efficiency, can be advantageously improved.A "steer-by-wire steering device" is to be understood in this context as meaning, in particular, at least a part, in particular a subassembly, of a steering system, in particular a steering system designed as a steer-by-wire steering system, and, in particular, of a vehicle. In particular, the steering system can also comprise further components and / or assemblies, such as, for example, at least one control unit and / or at least one wheel steering angle actuator, which is designed, for example, as a steering gear. In this case, the steering system is free of a direct mechanical connection between the steering handle and the wheel steering angle actuator, which is also referred to as a "steering rack actuator" in particular in this case, in particular in at least one operating state.Furthermore, a "steering function unit" is to be understood to mean, in particular, a unit which is different from the wheel steering angle actuator and is preferably in direct mechanical connection with the steering handle and is provided for the purpose of detecting signals, forces and / or torques from the steering handle, in particular directly, and / or transmitting them to the steering handle, in particular directly. In particular, the steering function unit is provided at least for generating the steering resistance and / or the restoring torque on the steering handle. In addition, the steering function unit is advantageously provided for detecting steering angle information. In addition, the steering function unit can preferably also be provided to adapt a steering feel perceptible by a driver via the steering handle and / or to provide the driver with haptic feedback from a subsurface and / or from vehicle wheels of the vehicle via the steering handle. For this purpose, the steering function unit can in particular comprise at least one detection unit and / or at least one actuator unit. In addition, the steering function unit can comprise at least one arithmetic unit for processing the signals and / or for controlling the actuator unit. In particular, the steering function unit is provided to maintain at least one degraded operation of the steer-by-wire steering device in at least one fault operating state in which, in particular, there is a fault and / or defect in the detection unit, the actuator unit, the arithmetic unit and / or an energy supply. In particular, the steer-by-wire steering device thus comprises at least one fallback level in the present case. "Provided" is to be understood in particular as being specially programmed, designed and / or equipped. The fact that an object is provided for a specific function is to be understood in particular to mean that the object fulfills and / or executes this specific function in at least one application state and / or operating state.A "detection unit" is to be understood in particular as a unit which is operatively connected in particular to the steering handle and which is provided at least for a contact-type and / or advantageously contactless detection of the steering angle information. In particular, the detection unit comprises at least one steering angle sensor for this purpose. The detection unit can, however, advantageously also comprise a plurality of steering angle sensors which can preferably cooperate for detecting the steering angle information. In addition, the detection unit is provided in particular for providing the steering angle information and / or a detection signal correlated with the steering angle information and forwarding it, in a lead-bound manner, to the wheel steering angle actuator. An "actuator unit" is to be understood in particular as a unit which is in particular operatively connected to the steering handle and which advantageously comprises at least one electric motor and is in particular at least provided for transmitting haptic feedback to the steering handle. Furthermore, a "computing unit" is to be understood to mean, in particular, an electrical and / or electronic unit which has an information input, an information processing and an information output. The computing unit advantageously further comprises at least one processor, at least one memory, at least one input and / or output means, at least one operating program, at least one control routine, at least one control routine and / or at least one calculation routine.It is furthermore proposed that the rack and pinion gear comprises at least one rack, in particular the rack already mentioned above, which is connected to the steering handle in such a way that a steering movement on the steering handle leads to a linear displacement of the rack, in particular in an at least substantially axial direction with respect to the steering handle. A "displacement in a direction at least substantially axial with respect to the steering handle" is to be understood in particular as a displacement in a direction which is oriented such that the toothed rack is displaced in a direction facing away from the steering handle and / or facing the steering handle, in particular such that a minimum distance between the toothed rack and the steering handle increases and / or decreases. In this way, in particular, a required installation space can be reduced.In the present case, the steering function unit comprises at least one actuator unit coupled to the rack and pinion gear, in particular the actuator unit already mentioned above, which is provided in particular to transmit a counter torque to the rack and pinion gear. In the present case, the actuator unit is provided at least for the purpose of providing haptic feedback to the gear rack via the gear rack mechanism.In order to transmit the steering handle. In this way, in particular flexibility can be increased and / or a required installation space can be further reduced. In particular, the components present can thereby be optimally used for the transmission of force between the actuator unit and the steering handle.It is furthermore proposed that the rack and pinion gear comprises at least one rack which is assigned to the steering handle and is connected in particular to the steering handle, and at least one drive pinion which is assigned to the actuator unit and is connected in particular to the actuator unit. In this way, in particular an advantageously simple force transmission can be achieved.If the actuator unit comprises at least one linear drive, such as a linear actuator and / or a linear motor, for example, which is directly coupled to the rack and pinion gear, in particular the drive pinion, a configuration which is almost neutral in terms of installation space can advantageously be achieved.Alternatively or additionally, it is proposed that the actuator unit comprises at least one rotary drive, such as an electric motor designed as a rotary motor, for example, and at least one connecting gear, in particular a belt gear, for connecting the rotary drive to the rack gear, in particular the drive pinion. In this way, in particular an advantageously cost-effective configuration can be provided.In the present case, the actuator unit comprises at least one detection unit for detecting steering angle information from the steering handle. The detection unit is provided to determine the steering angle information on the basis of a position of a rack of the rack and pinion gear, in particular the rack already mentioned above. Furthermore, the detection unit can be provided to ascertain the steering angle information on the basis of a position of a rotor of the actuator unit, in particular a rotor position of a rotor designed as a rotor or a linear position of a linearly movable rotor. This allows an advantageously simple and / or rapid detection of the steering angle information to be achieved.It is preferably further proposed that the steering function unit comprises at least one independent further detection unit for detecting steering angle information from the steering handle, which is in particular designed as a two-channel torque angle sensor. In this way, in particular, an advantageously redundant and / or functionally reliable detection of the steering angle information can be achieved.A particularly simple design can be achieved in particular if the steer-by-wire steering device comprises at least one coupling gear, which is arranged in particular between the steering handle and the steering function unit, connects the steering handle to the steering function unit and converts a steering movement on the steering handle into a movement of the rack gear. The coupling gear is preferably provided to convert a rotational movement and / or rotational movement on the steering handle into a translational movement and / or linear movement of the rack of the rack gear. For this purpose, the coupling gear can be designed, for example, as a push crank gear, as an articulated connecting rod gear and / or as a crank gear or the like.The steer-by-wire steering device is not intended to be limited to the application and embodiment described above. In particular, in order to fulfil a mode of operation described herein, the steer-by-wire steering device can have a number which differs from a number of individual elements, components and units mentioned herein.DRAWINGSFurther advantages are evident from the following description of the drawings. Exemplary embodiments of the invention are illustrated in the drawings. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations.The following are shown: FIG. 1 shows at least a part of an exemplary steering system designed as a steer-by-wire steering system with a steer-by-wire steering device in a simplified illustration, and FIG. 2 shows a simplified illustration of a further exemplary embodiment of a steer-by-wire steering device.DESCRIPTION OF THE EMBODIMENTSFIG. 1 shows at least a portion of an example steering system 38 ain a simplified illustration. The steering system 38 ais provided for use in a vehicle (not shown), in particular a motor vehicle. In a installed state, the steering system 38 acomprises an operative connection with vehicle wheels of the vehicle and is provided for influencing a direction of travel of the vehicle. Furthermore, the steering system 38 ais designed in the present case as a steer-by-wire steering system, in which a steering command is exclusively electrically forwarded to the vehicle wheels in at least one operating state.The steering system 38a has a wheel steering angle actuator (not shown) which is known per se and which is also referred to in the present case as a "steering rack actuator". The wheel steering angle actuator has an operative connection with at least two of the vehicle wheels, in particular two front wheels, and is provided for converting a steering specification into a steering movement of the vehicle wheels.The steering system 38 afurther includes a steer-by-wire steering device. The steer-by-wire steering device has a steering handle 10 a, in the present case embodied in particular as a steering wheel. The steering handle 10 aserves for applying a manual steering torque and is provided in particular for manually controlling the direction of travel of the vehicle, in particular by a driver. Alternatively, a steering handle could also be designed as a steering lever and / or steering ball or the like.The steer-by-wire steering device further includes a steering function unit 12 a. The steering function unit 12 ais assigned to the steering handle 10 a. The steering function unit 12 ais mechanically connected to the steering handle 10 a. The steering function unit 12 ain this case forms a single, coherent assembly which is also referred to as a "steering wheel actuator". The steering function unit 12 ais furthermore connected purely electrically to the wheel steering angle actuator. In the present case, the steering function unit 12 ais connected to the wheel steering angle actuator via at least two separate data connections 40 a. In addition, the steering function unit 12 ais connected via at least two separate and independent energy supply lines 42 ato at least one energy supply unit (not illustrated), such as a vehicle electrical system, for example, and advantageously to at least two different and independent energy supply units (not illustrated).The steering function unit 12 ais provided to detect signals, forces and / or torques from the steering handle 10 a, in particular directly, and / or to transmit them to the steering handle 10 a, in particular directly. In the present case, the steering function unit 12 ais provided at least for generating a steering resistance and / or a restoring torque on the steering handle 10 a. In addition, the steering function unit 12 ais provided for detecting steering angle information from the steering handle 10 a. In addition, the steering function unit 12 ais provided to adapt a steering feel perceptible by a driver via the steering handle 10 aand in the process to provide the driver with haptic feedback from a ground and / or from the vehicle wheels via the steering handle 10 a.The steering function unit 12 ais constructed in such a way that it can maintain at least a degraded operation of the steer-by-wire steering device in a fault operating state in which a fault and / or defect of a component of the steering function unit 12 aoccurs and / or a fault and / or a failure of a power supply exists.Moreover, the steer-by-wire steering device has a coupling gear 36 a. The coupling gear 36 ais arranged between the steering handle 10 aand the steering function unit 12 a. The coupling gear 36 aconnects the steering handle 10 ato the steering function unit 12 a. In the present case, the coupling gear 36 ais provided to convert a rotational movement on the steering handle 10 ainto a translatory movement and to feed it to the steering function unit 12 a. The coupling gear 36 acan be designed, for example, as a push-type crank gear, as a articulated connecting rod gear and / or as a crank gear or the like. In principle, however, it is also conceivable to dispense with a coupling gear and couple a steering handle directly to a steering function unit.A configuration of the steering function unit 12 awill be described in detail below.The steering function unit 12 aincludes an actuator unit 22 a. The actuator unit 22 ais connected to one of the data connections 40 aand to one of the energy supply lines 42 a. The actuator unit 22 aincludes at least one linear drive 24 a. In the present case, the linear drive 24 ais designed as a linear motor, in particular in the form of an electric motor. The actuator unit 22 ais at least provided for transmitting haptic feedback to the steering handle 10 a. Alternatively, an actuator unit could also comprise a rotary drive and / or a plurality of drives.In addition, the steering function unit 12 aincludes a rack and pinion gear 14 a. The rack and pinion gear 14 ais arranged between the actuator unit 22 aand the steering handle 10 a, in the present case in particular between the actuator unit 22 aand the coupling gear 36 a. The rack and pinion gear 14 ais coupled to the actuator unit 22 aand to the coupling gear 36 a. The rack and pinion gear 14 ais provided for a connection and a transmission of force between the actuator unit 22 aand the steering handle 10 a.The rack and pinion gear 14a has a rack 16a. The rack 16a is associated with the steering handle 10a. The rack 16a is connected, in particular via the coupling gear 36a, to the steering handle 10a. The rack 16 ais connected to the steering handle 10 in such a way that a steering movement at the steering handle 10 aresults in a linear displacement of the rack 16 ain an axial direction 20 arelative to the steering handle 10 a. The coupling gear 36 ais thus provided to convert a steering movement at the steering handle 10 ainto a movement of the toothed rack 16 a. In principle, however, a toothed rack could also be mounted so as to be displaceable in a direction perpendicular to an axial direction shown.Furthermore, the rack and pinion gear 14a has a drive pinion 18a coupled to the rack 16a. The drive pinion 18 ais assigned to the actuator unit 22 a. The drive pinion 18 ais connected directly to the actuator unit 22 a, in particular to the linear drive 24 a. In the present case, the drive pinion 18 ais connected to the actuator unit 22 ain such a way that the actuator unit 22 acan introduce a counter torque into the rack gear 14 avia the drive pinion 18 aand can transmit a haptic feedback to the steering handle 10 avia the rack 16 a. Alternatively, however, a drive pinion could also be coupled to an actuator unit via an additional connecting transmission.For detecting the steering angle information from the steering handle 10 a, the actuator unit 22 afurther comprises at least one detection unit 30 a. In the present case, the detection unit 30 ais provided to ascertain the steering angle information on the basis of a position of the rack 16 aand / or on the basis of a position of a rotor of the actuator unit 22 a, in particular of the linear drive 24 a. In order to ensure that a maximum deflection of the rack 16 aand / or of the rotor of the actuator unit 22 acoincides with an end stop angle of the steering handle 10 a, the position of the rack 16 aand / or the position of the rotor of the actuator unit 22 ais advantageously calibrated accordingly. In principle, however, the detection unit 30a could also be dispensed with.In addition, the steering function unit 12 aincludes an independent further detection unit 32 afor, in particular redundant, detection of the steering angle information from the steering handle 10 a. The further detection unit 32 ais connected to a further one of the data connections 40 aand to a further one of the energy supply lines 42 a. The further detection unit 32 ais designed in the present case as a two-channel torque angle sensor, for example. Alternatively, however, it is also conceivable to design a further detection unit as a conventional steering angle sensor and / or torque sensor.In addition, a further detection unit could in principle also be dispensed with.By means of the detection unit 30 aand the further detection unit 32 aand in particular their redundant configuration, the steering angle information can thus be forwarded from the steering handle 10 ato the wheel steering angle actuator at any time. In addition, the rack and pinion gear 14 aand in particular its inherent high friction can ensure, even in the event of failure of the actuator unit 22 aand / or failure of the actuator unit 22 abecause of insufficient energy supply, that the steering handle 10 adoes not move in an uncontrolled manner owing to a lack of steering resistance and / or restoring torque, as a result of which operational reliability of the steering system 38 acan advantageously be increased.In FIG. 2 a further embodiment of the invention is shown. The following description and the drawing are limited substantially to the differences between the exemplary embodiments, wherein with regard to identically denoted components, in particular with regard to components with the same reference numerals, reference can in principle also be made to the drawings and / or the description of the other exemplary embodiments, in particular FIG. 1. To distinguish between the exemplary embodiments, the letter a is appended to the reference numerals of the exemplary embodiment in FIG. 1. In the exemplary embodiment of FIG. 2, the letter a is replaced by the letter b. The further exemplary embodiment of FIG. 2 differs from the previous exemplary embodiment at least substantially in terms of a configuration of an actuator unit 22 bof a steering function unit 12 b.In this case, the actuator unit 22 bhas at least one rotary drive 26 b, such as an electric motor designed as a rotary motor, for example, and at least one connecting gear 28 bfor connecting the rotary drive 26 bto a rack gear 14 b, in particular a drive pinion 18 bof the rack gear 14 b. The connecting transmission 28 bis designed here as a belt transmission, for example. In principle, however, a connecting transmission could also be designed as any connecting transmission that deviates from a belt transmission.

Claims

Steer-by-wire steering device having at least one steering handle (10a) and having at least one steering function unit (12a; 12b) which is provided at least for generating a steering resistance and / or a restoring torque on the steering handle (10a), characterized in that the steering function unit (12a; 12b) comprises at least one rack and pinion gear (14a; 14b).Steer-by-wire steering device according to Claim 1, characterized in that the rack and pinion gear (14a; 14b) comprises at least one rack (16a), which is connected to the steering handle (10a) in such a way that a steering movement on the steering handle (10a) leads to a linear displacement of the rack (16a) in an at least substantially axial direction (20a) with respect to the steering handle (10a).Steer-by-wire steering device according to Claim 1 or 2, characterized in that the steering function unit (12a; 12b) comprises at least one actuator unit (22a; 22b) which is coupled to the rack and pinion gear (14a; 14b) and is provided at least for transmitting haptic feedback to the steering handle (10a) via the rack and pinion gear (14a; 14b).Steer-by-wire steering device according to Claim 3, characterized in that the rack and pinion gear (14a; 14b) comprises at least one rack (16a) assigned to the steering handle (10a) and at least one drive pinion (18a; 18b) assigned to the actuator unit (22a; 22b).Steer-by-wire steering device according to Claim 3 or 4, characterized in that the actuator unit (22a) comprises at least one linear drive (24a), which is directly coupled to the rack and pinion gear (14a).Steer-by-wire steering device according to one of Claims 3 to 5, characterized in that the actuator unit (22b) comprises at least one rotary drive (26b) and at least one connecting gear (28b), in particular a belt gear, for connecting the rotary drive (26b) to the rack and pinion gear (14b).Steer-by-wire steering device according to one of Claims 3 to 6, characterized in that the actuator unit (22a; 22b) comprises at least one detection unit (30a) for detecting steering angle information from the steering handle (10a), wherein the detection unit (30a) is provided for the purpose of determining the steering angle information on the basis of a position of a toothed rack (16a) of the toothed rack gear mechanism (14a; 14b) and / or on the basis of a position of a rotor of the actuator unit (22a; 22b).Steer-by-wire steering device according to one of the preceding claims, characterized in that the steering function unit (12a; 12b) comprises at least one independent further detection unit (32a) for detecting steering angle information from the steering handle (10a), which is designed as a two-channel torque angle sensor.Steer-by-wire steering device according to one of the preceding claims, characterized byat least one coupling gear (36a) which connects the steering handle (10a) to the steering function unit (12a; 12b) and converts a steering movement on the steering handle (10a) into a movement of the rack and pinion gear (14a; 14b).Steering system (38a) having at least one steer-by-wire steering device according to one of the preceding claims.

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