Device for determining the position of a steering rod for a steering unit, steering unit and use of the device in a steering unit

Abstract

The invention relates to a device (1) for determining the position of a handlebar (2) for a steering unit, in particular a steer-by-wire steering unit, of a vehicle, wherein the device (1) comprises: an oscillating body (4) with a first axial end (8) and a second axial end (10), wherein the first axial end (8) is designed to be fastened to a component (3) fixed to the body, and the second axial end (10) is designed to be free, a coupling unit (5) for fastening to the handlebar (2), wherein the coupling unit (5) has at least one bearing element (19) for supporting the oscillating body (4) and is arranged so as to be axially displaceable relative to the oscillating body (4), and a sensor device (6) for determining the position of the handlebar (2), which sensor device is designed to detect an oscillation frequency of the oscillating body (4).

Description

[0001] The present invention relates to a device for determining the position of a steering rod for a steering unit, in particular a steer-by-wire steering unit, of a vehicle, a steering unit for a vehicle and a use of such a device in a steering unit of a vehicle. State of the art

[0002] Today, both mechanical steering systems or steering units and so-called steer-by-wire steering systems or steering units are known. Steering systems can be divided into two subsystems: the system of the steering shaft with a steering element, such as a steering wheel, which is also referred to as a “hand wheel actuator” (HWA) system, and the system of the steering actuator for steering the wheels, which is also referred to as the “road wheel actuator” (RWA) system. In mechanical steering systems, these two subsystems are mechanically connected to one another via the steering column and, if applicable, a steering gear. In mechanical steering systems, the two subsystems are therefore directly, i.e. physically, connected to one another. In these mechanical steering systems, the position of the steering element is always uniquely linked to the position of the steering actuator, in particular a steering rod.This means that a specific position of the steering element is uniquely assigned to a specific position of the handlebar, so that each position of the handlebar is assigned to a specific position of the steering element.

[0003] Steer-by-wire steering systems dispense with the mechanical connection between the two subsystems via the steering column, and the steering of the wheels, in response to a movement of the steering element, is controlled by transmitting corresponding signals between the two subsystems, HWA and RWA. In other words, with steer-by-wire steering systems, the physical steering column, which transmits the steering movement or driver input from the steering wheel directly via the steering gear, tie rod, and wheel carrier to the wheel, is replaced by electrically redundant "by wire"—i.e., signal transmission via cable. As a result, the position of the steering element is no longer physically linked to the position of the handlebar. Such a unique link between the position of the steering element and the position of the handlebar is typically achieved with sensors located in the RWA system that serve to determine the position of the handlebar.Various sensor arrangements are known, for example from WO 2018 / 073267 A1, DE 11 2020 002 949 T5, DE 10 2021 212 470 A1.

[0004] It has now become apparent that there is a further need to improve a known device for determining the position of the steering rod for a steering unit, in particular a steer-by-wire steering unit, of a vehicle. In particular, there is a further need to provide a device for determining the position of the steering rod that allows the position of the steering rod to be determined absolutely, and furthermore, in particular, even after the vehicle has been switched off or de-energized.

[0005] Against this background, it is an object of the present invention to provide an improved device for determining the position of a handlebar for a steering unit, in particular a steer-by-wire steering unit, of a vehicle, which device enables in particular an absolute, further in particular constant, determination of the handlebar position. Disclosure of the invention

[0006] These and other objects, which will be mentioned upon reading the following description or which may be recognized by a person skilled in the art, are achieved by the subject matter of the independent claim. Advantageous embodiments and further developments can be found in the dependent claims and the following description.

[0007] The device according to the invention for determining the position of a handlebar for a steering unit, in particular a steer-by-wire steering unit, of a vehicle has an oscillating body, a coupling unit for attachment to the handlebar, and a sensor device for determining the position of the handlebar. The oscillating body has a first axial end and a second axial end opposite the first axial end, wherein the first axial end is designed to be attached, in particular clamped, to a body-fixed component, e.g., to a housing of the handlebar, and wherein the second axial end is designed to be freely oscillatable. The coupling unit has at least one bearing element for supporting the oscillating body and is arranged to be axially displaceable relative to the oscillating body, in particular between the first axial end and the second axial end of the oscillating body.The sensor device for determining the position of the handlebar is designed to detect an oscillation frequency, in particular a resonance frequency, of the oscillating body.

[0008] The steering rod can be designed as a wheel axle that connects the two wheels to be steered, which are opposite each other in the width direction of the vehicle. For example, the steering rod can be designed as a front wheel axle and / or a rear wheel axle.

[0009] The oscillating body is designed, in particular, as an oscillating beam, e.g., as a leaf spring. The sensor device for detecting the oscillation frequency comprises at least one sensor, e.g., a microphone, in particular a structure-borne sound microphone, a piezoelectric sensor, strain gauges, a capacitive sensor, or an inductive sensor.

[0010] The advantage of the solution according to the invention lies in particular in the fact that the oscillating body is coupled to the handlebar via the coupling unit, which can be firmly coupled to the handlebar. Thus, the position of the coupling unit relative to the oscillating body changes with the translational movement of the handlebar along its longitudinal axis. As a result, the free length of the oscillating body, and thus the resonant frequency of the oscillating body, changes proportionally to the handlebar position. The handlebar position can be uniquely determined from the frequency of the oscillating body, which is different for each handlebar position. One could also say that the oscillating body functions as a separate oscillator, like a variable tuning fork, so to speak.

[0011] Frequency-based determination of the position of the handlebar is particularly insensitive to interference, such as signal noise or signal offset. This makes it possible to determine the position of the handlebar as accurately as possible even when the signal paths are long and / or in noisy environmental conditions, such as electromagnetic interference in the connecting lines between the sensor and a control unit, are present. For example, powerful electric motors, their control systems, high-voltage ignition devices in gasoline engines, etc., are particularly susceptible to interference. Furthermore, frequency-based determination of the position of the handlebar enables high accuracy in determining the position, as frequency-based determination is insensitive to typical sources of deviations or inaccuracies in the measurement, such as play in bearings, play in the screw drive, wear, etc.

[0012] In other words, the device according to the invention makes it possible to unambiguously determine the position of the handlebar, and thus the absolute steering angle of the wheels to be steered, and thus to know it at all times. This makes it possible to unambiguously determine the position of the handlebar at any time, even without using a steering angle sensor on a steering column in the steering column control unit and / or on a steering shaft pinion. As a result, the device according to the invention is particularly suitable for use with steer-by-wire steering units, where determining the position of the handlebar using conventional steering angle sensors is not possible because there is no mechanical connection to the steering wheel and / or the steering shaft pinion is missing.

[0013] Knowing the position of the steering rod prevents both misalignments of the steering element, i.e. a position of the steering element that is perceived as "wrong", e.g. with the wheels pointing straight ahead, a position of the steering element that is inclined / tilted to one side, which can have an impact on the driving experience of a driver of the vehicle but does not affect the functionality of the vehicle, as well as incorrect steering movements of the wheels, which can result in serious, particularly dangerous errors, particularly with regard to driver assistance systems, and / or cause damage to mechanical components.

[0014] The term "absolute", in relation to "absolute position of the handlebar", means that at any time from the measurement signal based on the recorded vibration frequency and / or a combination of several measurement signals from different sensor devices, e.g. with the determination of the rotational position of an actuator, which is designed to move the handlebar along its longitudinal axis, by means of a position sensor, the determination of the absolute position of the handlebar is possible.

[0015] According to one embodiment, the device further comprises an evaluation unit configured to determine a position of the handlebar in the axial direction, in particular with respect to a predetermined zero position, based on the oscillation frequency detected by the sensor device. The sensor device and the evaluation unit can be formed separately from one another or integrally in one piece. If the evaluation unit is formed separately from the sensor device, the evaluation unit can be provided, for example, in a control unit of the vehicle, and the sensor device sends the signal it generates based on the detected frequency to the evaluation unit, which then determines the position of the handlebar based on this signal.If the sensor device and the evaluation unit are provided as a single piece, the evaluation unit is integrated into the sensor device, so to speak, and the determination of the position of the handlebar based on the detected frequency is performed by the sensor device. In this case, a signal sent by the sensor device, for example, to a control unit of the vehicle, corresponds to the position of the handlebar determined based on the detected frequency.

[0016] According to one embodiment, the device further comprises a vibration exciter, in particular a controllable one, which is configured to excite the oscillating body to vibrate. The vibration exciter is used in particular to determine the position of the handlebar when the vehicle is stationary, e.g., when starting the vehicle, i.e., before starting a journey, etc. Furthermore, the oscillating body can also be excited to vibrate by external influences, such as vibrations during travel.

[0017] According to one embodiment, the vibration exciter is designed as an additional integrated actuator. The vibration exciter designed as an integrated actuator can, in particular, be designed integrally with the sensor device. This means that the vibration exciter and the sensor device are designed as a single component. This allows both the installation space and the total number of parts of the device to be reduced. Furthermore, it is possible to simplify production and / or assembly. Furthermore, the integral, single-piece design allows safety-critical connection points between the components - if designed separately - to be avoided.

[0018] According to one embodiment, the device comprises an oscillating mass arranged at the second axial, free end of the oscillating body. The oscillating mass is an additional mass which, arranged at the second axial, free end of the oscillating body, amplifies the deflection at the free end of the oscillating body that is coupled to the frequency of the oscillating body, and thus simplifies the detection of the frequency of the oscillating body and / or enables the accuracy of detecting the frequency of the oscillating body to be increased. In other words, one can say that the additional mass makes it possible to shift the frequency, in particular the resonant frequency, of the oscillating body into a more measurable or detectable, i.e., usable, range. Furthermore, the additional mass can increase the amplitude of the oscillation.In addition, the oscillating mass can be made of metal and thus serve as a metal core, in particular as an iron core, in a coil and thus be part of the sensor device.

[0019] According to one embodiment, the oscillating mass is designed as an element separate from the oscillating body, which is attached to the second axial, in particular free, end, e.g., a rivet bolt. An oscillating mass designed as a separate element enables the use of existing elements, in particular standard elements such as a rivet bolt, etc., and thus a cost-effective implementation of the oscillating mass on the oscillating body.

[0020] According to one embodiment, the oscillating mass is formed integrally with the oscillating body, e.g., as a 90° angled oscillating body end or as a 180° folded oscillating body end section. No separate elements are required for this, thus reducing the total number of parts. For the sake of completeness, it is explicitly pointed out here again that the second axial, free end of the vibrating body cannot have any additional mass, whereby the reshaping of the vibrating body end is defined as "no additional mass." This can, for example, result in favorable vibration frequencies in certain frequency ranges, similar to a guitar string.

[0021] According to one embodiment, the sensor device comprises a sensor coil configured to detect the oscillation frequency at the second axial end. Furthermore, it is also conceivable to use the sensor coil as a vibration exciter. In particular, the sensor coil is arranged to at least partially surround the second axial, free end of the oscillating body, e.g., in the region of the oscillating mass. Furthermore, the sensor device, in particular in addition to the sensor coil, has a permanent magnet. The coil can, for example, be energized in a pulsed manner to cause a deflection of the second axial, free end of the oscillating body, thus acting as a vibration exciter. Furthermore, the sensor coil can be used to detect the oscillation frequency, in particular directly after the excitation of the oscillating body.One can therefore say that the sensor device and the vibration exciter can be controlled in such a way that the sensor coil is temporarily energized as a vibration exciter and alternately used as a sensor for detecting the vibration frequency. In this case, the vibrating body and / or the vibrating mass in particular comprises a magnetizable or magnetized material, e.g., ferritic stainless steel. When the position of the vibrating body changes, the magnetic field induced by the vibrating body changes, thereby inducing a current flow in the sensor coil. Additionally, or alternatively, conversely, by controlling the sensor coil, a current flow can be induced in the coil, thereby exerting a force change on the vibrating body, which serves to excite vibration.

[0022] According to one embodiment, the device comprises a preloading element configured to preload the oscillating body in such a way that a coupling, in particular a play-free one, is ensured between the at least one bearing element of the coupling unit and the oscillating body. The preloading element can be designed as a separate element or integrally formed with the oscillating body or integrally formed with the coupling unit. The wording "integrally formed" is to be understood here in particular as "together with the oscillating body or the coupling unit as a component."

[0023] According to one embodiment, the preload element is arranged in a longitudinal direction of the oscillating body between the first axial end and the coupling unit. Additionally or alternatively, the preload element is arranged in a longitudinal direction of the oscillating body between the coupling unit and the second axial end. By positioning the preload element, the oscillation frequency and the oscillation shape can be influenced or changed. Thus, the position of the preload element can be selected depending on the required measuring path and oscillating body design.

[0024] According to one embodiment, the oscillating body is designed as a leaf spring. Leaf springs are particularly cost-effective and / or can be manufactured in large quantities or as rolls. Alternatively, the oscillating body can also be designed as an oscillating beam, e.g., as a round rod.

[0025] According to one embodiment, the coupling unit has a spring device configured to press the at least one bearing element against the oscillating body. This allows the at least one bearing element to be preloaded against the oscillating body, thereby compensating for manufacturing and / or component-related tolerances. This allows a play-free coupling of the oscillating body to the handlebar and / or increases the accuracy of detecting the oscillation frequency. The spring device can therefore also be said to function as a tolerance compensation element. The spring device can, for example, be designed as a compression spring. Furthermore, it is conceivable that a preload of the spring device can be adjusted in a suitable manner, for example, via a lever.

[0026] According to one embodiment, the coupling unit comprises a plurality of bearing elements arranged on both sides of the oscillating body, i.e., above and below the oscillating body, as viewed in the direction of oscillation. The bearing elements, in combination, act like clamping points on the oscillating body, and the oscillating body can be preloaded within the coupling unit by the position of the bearing elements relative to one another, particularly as viewed in the direction of oscillation. Thus, with such a coupling unit, additional, particularly separately provided, preload elements can be dispensed with.

[0027] For example, the coupling unit can have three bearing elements that are offset from one another in the longitudinal direction of the vibrating body and are arranged alternately below and above the vibrating body in the direction of vibration of the vibrating body, contacting the vibrating body. Alternatively, the coupling unit can have, for example, four bearing elements that are arranged in pairs opposite one another above and below the vibrating body in the direction of vibration of the vibrating body, contacting the vibrating body, and are arranged spaced apart / adjacent to one another in the longitudinal direction of the vibrating body.

[0028] According to one embodiment, the coupling unit further comprises a clamping element, e.g. a screw, which is designed to adjust a height distance in the direction of oscillation of the oscillating body, as seen in the longitudinal direction, of the middle bearing element. This allows the middle bearing element to be preloaded against the oscillating body, whereby manufacturing and / or component-related tolerances can be compensated. In this way, a play-free coupling of the oscillating body to the handlebar can be achieved and / or the accuracy of the detection of the oscillation frequency can be increased. One can therefore also say that the clamping element functions as a tolerance compensation element. The clamping element can, for example, be designed as a screw.

[0029] According to one embodiment, the bearing elements are designed as rollers or as sliding sections, e.g., sliding pads. Furthermore, it is conceivable that at least one bearing element designed as a roller can have a collar on both sides, wherein the oscillating body is guided by this collar formed on both sides by the oscillating body being laterally enclosed by the collar. One could therefore also say that the at least one bearing element designed as a roller has an enlarged diameter on both sides, which forms the collar present on both sides. A firmly clamped, correspondingly strong oscillating body can thus simultaneously serve as an anti-twist device for the handlebar.

[0030] It is conceivable for the coupling unit to be designed, for example, as an injection-molded part made of a plastic, in particular of a fiber-reinforced plastic, on which the at least one bearing element is provided integrally, e.g. as a sliding region. Optionally, metallic elements, e.g. metallic spring elements, can be integrated, i.e. injected, during the injection-molding process. Alternatively, it is also conceivable for the coupling element to be designed from a sheet metal material which has fastening regions, e.g. elastically designed fingers, to which the bearing elements can be fastened, in particular clipped, in a suitable manner. In the context of this application, the term "plastic" encompasses a single-variety plastic, a plastic mixture, a fiber-reinforced plastic, and a fiber-reinforced plastic mixture.

[0031] A further aspect of the invention relates to a steering unit, in particular a steer-by-wire steering unit, for a vehicle. The steering unit has a handlebar, a control actuator, and a device according to the present invention. The handlebar is configured to be coupled at its axial ends to a wheel of a vehicle. The control actuator is coupled to the handlebar such that a rotational movement of the control actuator causes a translational movement of the handlebar along its longitudinal axis. The coupling unit of the device is fastened to the handlebar. The at least one bearing element of the coupling unit is axially displaceable relative to the oscillating body by the translational movement of the handlebar, and the sensor device for determining the position of the handlebar is configured to detect the oscillation frequency of the oscillating body.

[0032] The actuator is designed, in particular, as an electric motor. The actuator can be coupled to the handlebar, for example, via a belt drive, whereby the belt drive enables a rotational movement of the actuator into a translational movement of the handlebar along its longitudinal axis. For this purpose, the belt drive is coupled, in particular, to a linear gear, such as a ball screw drive or a planetary roller screw drive. An electric motor as the actuator enables a rotational movement in two opposing directions, making it possible to move the handlebar along its longitudinal axis in one direction or the other, depending on the selected direction of rotation. In other words, one can say that the actuator enables the handlebar to move translationally back and forth along its longitudinal axis.

[0033] The coupling unit of the device is attached to the handlebar in such a way that the coupling unit, together with the handlebar, moves axially relative to the oscillating body when the handlebar is moved along its longitudinal axis. As a result, the position of the coupling unit relative to the oscillating body changes in accordance with a change in the position of the handlebar. The position of the coupling unit relative to the oscillating body influences the oscillating frequency of the oscillating body in such a way that each position of the coupling unit relative to the oscillating body can be assigned a specific oscillating frequency, in particular a specific resonant frequency. Since the position of the coupling unit relative to the oscillating body is directly related to the position of the handlebar, the position of the handlebar can be determined using the oscillating frequency of the oscillating body.

[0034] Thus, the device for determining the position of the handlebar, in particular the absolute position of the handlebar, generally operates independently and can essentially determine the position of the handlebar on its own with sufficiently high accuracy, resolution and reliability and output it as an output signal.

[0035] However, it is also possible to combine the output signal of the device for determining the position of the handlebar with another signal, in particular the signal from a position sensor, e.g., a rotor position sensor, from the actuator. The rotor position sensor generally provides a highly precise signal corresponding to an electrical or mechanical angle of the rotor, which is required to control the actuator, which can be designed, in particular, as an electric motor. The angle of the rotor is highly proportional to the position of the handlebar, in particular usually about 2-5 mm / rev, but - considered on its own - does not allow the absolute position of the handlebar to be determined, since the angle of the rotor performs several complete revolutions over the entire travel range of the handlebar, which can also be referred to as the handlebar travel, e.g., on the order of about 20-100 revolutions.In combination with the device described above, in particular according to the invention, a precise determination of the position of the handlebar, in particular the absolute position of the handlebar, is now possible. The device only needs to have a low resolution or accuracy, since the device only needs to perform a rough determination of the position of the handlebar, while the rotor position sensor provides the high resolution or accuracy, so to speak, the decimal places. Such a combination can make it possible to further improve the resolution and accuracy.

[0036] This allows the costs of the device for determining the position of the handlebar to be reduced, as the demands placed on the device are lower than in a case where the device alone, i.e. independently, must deliver the high accuracy or resolution. Even in a case where the rotor position sensor fails during operation, it is possible to temporarily control the actuator using the device's signal, even if the resolution or accuracy of the device with respect to the angle of the actuator's rotor is rather low. Conversely, it is also possible to temporarily compensate for a failure of the device for determining the position of the handlebar during operation by incrementally "counting" the signal from the rotor position sensor, in particular at least as long as power is ensured to the rotor position sensor and, if applicable, an associated control unit.

[0037] Furthermore, continuous monitoring of the signal from the rotor position sensor and the signal from the steering rod position sensor can detect implausible discrepancies in the signals, which could indicate, for example, a belt jump and / or belt wear. This allows for early detection of incipient mechanical failure.

[0038] According to one embodiment, the steering unit further comprises an evaluation unit, e.g. a control unit, which is configured to determine a position of the handlebar based on the oscillation frequency detected by the sensor device.

[0039] The evaluation unit can be provided separately from the sensor device or integrated into the sensor device. If the evaluation unit is designed separately from the sensor device, the evaluation unit can be provided, for example, in a control unit or a control device of the vehicle and the sensor device sends the signal it generates based on the detected frequency to the evaluation unit, which then determines the position of the handlebar based on this signal. If the evaluation unit is integrated into the sensor device, the determination of the position of the handlebar based on the detected frequency can be carried out by the sensor device. In this case, a signal which is sent by the sensor device, for example to the control unit of the vehicle, corresponds to the position of the handlebar determined based on the detected frequency.

[0040] A further aspect of the present invention relates to a use of a device according to the present invention in a steering unit, in particular a steer-by-wire steering unit, of a vehicle for determining the position of the handlebar, wherein the position of the handlebar is determined based on the oscillation frequency detected by the sensor device. Detailed description based on drawing

[0041] Further measures improving the invention are described in more detail below, together with the description of preferred embodiments of the invention, with reference to the figures. It shows: Fig. 1 a schematic representation of a device for determining the position of a handlebar according to an embodiment of the invention in a side view, Fig. 2 a schematic representation of a device for determining the position of a handlebar according to an embodiment of the invention in a side view, Fig. 3 a schematic representation of a device for determining the position of a handlebar according to an embodiment of the invention in a side view, Fig. 4 a schematic representation of a device for determining the position of a handlebar according to an embodiment of the invention in a side view, and Fig. 5 a schematic representation of a device for determining the position of a handlebar according to an embodiment of the invention in a side view.

[0042] The figures are merely schematic and serve only to clarify the invention. The same elements are designated by the same reference numerals.

[0043] Fig. 1 to Fig. 5 show schematically and by way of example a device 1 for determining the position of a handlebar 2 according to various embodiments of the invention. Fig. 1 to Fig. The exemplary embodiments of the device 1 shown in Figure 5 are all arranged on a housing 3, which at least partially surrounds the handlebar 2. The handlebar 2 is mounted in the housing 3 so as to be axially displaceable relative thereto. The device 1 according to all in Fig. 1 to Fig. 5 each comprises an oscillating body 4, a coupling unit 5 and a sensor device 6. The Fig. 1 to Fig. The exemplary embodiments shown in Figure 5 differ essentially in the coupling unit 5.

[0044] The oscillating body 4 is in Fig. 1 to Fig. 5 is designed, for example, as a leaf spring 7, which is fastened to the housing 3 at a first axial end 8, wherein the fastening 9 is implemented in particular in the manner of a fixed clamping. A second axial end 10 of the oscillating body 4 is free, i.e. a so-called free end. At the second axial end 10, an oscillating mass 11 is arranged as a separate element, here in the form of a rivet bolt 12. The sensor device 6 is in Fig. 1 to Fig. 5, a sensor coil 13 is formed with a permanent magnet 14. The sensor device 6 can be controlled in such a way that the sensor coil 13 can be controlled both as a vibration exciter 15 for exciting vibration of the vibrating body 4 and as a sensor 16 for detecting the vibration frequency.

[0045] In Fig. 1, the coupling unit 5 is designed as a bearing block 17 with a bearing element 19 designed as a roller 18. The bearing block 17 is fixedly, in particular axially fixedly, coupled to the handlebar 2, such that the bearing block 17 moves together with the handlebar 2 along its longitudinal axis L relative to the oscillating body 4. In addition, in Fig. 1 a prestressing element 20 is arranged near the first axial end 8 contacting the oscillating body 4, which prestresses the oscillating body 4 in a direction of oscillation S against the coupling unit 5 in order to compensate for any tolerances and to ensure constant contact between the coupling unit 5, in particular the bearing element 19, and the oscillating body 4.

[0046] Depending on where the bearing element 19 is arranged due to the position of the handlebar 2 relative to the oscillating body 4, a length ratio varies from a first, in Fig. 1 left of the bearing block 17 arranged section 21 to a second, in Fig. 1 section 22 arranged to the right of the bearing block 17. The first section 21 of the oscillating body 4 extends in the axial direction A from the preload element 20 to a contact point between the bearing element 19 and the oscillating body 4 and can be referred to as a cooperating spring region. The second section 22 extends in the axial direction A from the contact point between the bearing element 19 and the oscillating body 4 and the second axial end 10 or the oscillating mass 11 and can be referred to as an oscillating beam or also as a freely oscillating end.

[0047] Each length ratio between the first subsection 21 and the second subsection 22 can be uniquely assigned its own vibration frequency, in particular a specific natural frequency or resonance frequency, which can be detected by the sensor device 6 at the freely vibrating end 22 or at the second axial end 10. Due to the unique assignment of a vibration frequency to a position of the bearing element 19 relative to the vibrating body 4, and because the coupling unit 5 comprising the bearing element 19 is firmly connected to the handlebar 2 and only moves together with the handlebar 2 relative to the vibrating body 4, the position of the handlebar 2, in particular the absolute position of the handlebar 2, can be determined based on the detected vibration frequency.

[0048] In the Fig. 2 and Fig. 3, the prestressing element 20 is arranged to the right of the contact point of the bearing element 19 with the oscillating body 4, as seen in the axial direction A, in particular in such a way that the first partial section 21 of the oscillating body 4, i.e. the cooperating spring region, extends in the axial direction A from the first axial end 8 to the prestressing element 20 (in Fig. 2 and Fig. 3, i.e. arranged to the left of the pre-tensioning element 20) and the second partial area 22 of the oscillating body 4, i.e. the free oscillating end, extends in the axial direction A between the pre-tensioning element 20 and the second free end (in Fig. 2 and Fig. 3, i.e., arranged to the right of the preload element 20). Due to the selected position for the preload element 20, a length of the freely swinging end remains constant. The coupling unit 5 in the form of the bearing block 17 moves in the area of ​​the first section 21, i.e., the spring area, relative to the oscillating body 4. This means that depending on where the bearing element 19 is arranged within the first section 21 due to the position of the handlebar 2 relative to the oscillating body 4, a length ratio between a first, in Fig. 2 and Fig. 3 spring area 23 arranged to the left of the bearing block 17 and a second, in Fig. 2 and Fig. 3 spring area 24 arranged to the right of the bearing block 17 varies.

[0049] Each length ratio between the first spring region 23 and the second spring region 24 can be uniquely assigned its own vibration frequency, in particular a specific natural frequency or resonance frequency, which can be detected by the sensor device 6 at the freely vibrating end 22 or at the second axial end 10. Due to the unique assignment of a vibration frequency to a position of the bearing element 19 relative to the vibrating body 4, and because the coupling unit 5 comprising the bearing element 19 is firmly connected to the handlebar 2 and only moves together with the handlebar 2 relative to the vibrating body 4, the position of the handlebar 2, in particular the absolute position of the handlebar 2, can be determined based on the detected vibration frequency.

[0050] The Fig. The embodiment shown in Figure 3 differs from that shown in Fig. 2 merely in that the bearing element 19 is pressed against the oscillating body 4 by means of a spring device 25, shown here as a compression spring 26 by way of example, and is thus prestressed, whereby a play-free contact between the bearing element 19 and the oscillating body 4 is ensured.

[0051] Fig. 4 and Fig. 5 show embodiments of the device 1, in which the coupling unit has a plurality of bearing elements 19, which are arranged in the oscillation direction S of the oscillating body 4 on both sides, i.e. both above and below the oscillating body 4, in contact with the oscillating body 4. By such a bilateral arrangement of the bearing elements 19, it is possible to select and / or adjust a distance in the oscillation direction S between the bearing elements 19 arranged on one side, e.g. above, of the oscillating body 4 and the bearing elements 19 arranged on the other side, e.g. below, of the oscillating body 4 in such a way that a preload of the oscillating body 4 is converted within the coupling unit 5 and thus to further, in particular separate, preload elements, such as the preload elements 20 in Fig. 1 and Fig. 2, can be waived.

[0052] Fig. 4 shows an embodiment in which the coupling unit is designed as a bearing block 27 with three bearing elements 19 designed as rollers 18. By positioning the rollers 18 closer to one another in the oscillation direction S, the oscillating body 4 is slightly bent and thus itself realizes the required preload. Since the distances in the axial direction A between the rollers 18, in particular between the clamping points of the rollers 18, remain constant, only the length of the free oscillating end 22 changes when the bearing block 27 is moved. This embodiment makes it possible to define the oscillation frequency, in particular the natural frequency, associated with each position very well, i.e., very precisely.

[0053] In Fig. 4 is not shown, but it is conceivable to further provide an adjusting element, e.g. a screw, in the bearing block 27, which is designed to selectably adjust a position of the central bearing element 19 in the oscillation direction S in order to compensate for possible tolerance fluctuations and to ensure a play-free mounting of the oscillating body 4 by the bearing block 27.

[0054] Fig. 5 shows an embodiment in which the coupling unit is designed as a bearing block 28 with four bearing elements 19 designed as rollers 18, which are arranged in pairs on the oscillating body 4 opposite one another in the oscillation direction S. In the Fig. 4, the preload due to the offset bearing elements 19 causes the second axial end 10, or the oscillating mass 11, to be slightly displaced from the central position 29 (see dashed line in Fig. 4). The longer the freely swinging end 22, the greater the deviation from the central position 29, whereby the preload generated by the bearing elements 19 is limited upwards. To avoid this, the bearing block 28 can be Fig. 5 shown embodiment with two bearing element pairs 30 arranged one above the other, wherein the bearing elements 19 of a bearing element pair 30 are preloaded relative to one another (in Fig. 5 visually illustrated by arrows).

[0055] Furthermore, the coupling unit 5, regardless of the respective embodiment, can serve, for example, as an end stop against the housing 3. Additionally, or alternatively, the coupling unit 5 can run laterally to the direction of travel of the handlebar 2 on the housing 3 in order to thus realize a suitable torque support of the handlebar 2. Furthermore, the bearing elements 19 can also be designed as sliding sections, e.g., sliding pads, instead of rollers 18 as shown here by way of example. List of reference symbols 1 device 2 handlebar 3 housings 4 oscillating bodies 5 Coupling unit 6 Sensor device 7 leaf spring 8 first axial end 9 Fastening 10 second axial end 11 Oscillating mass 12 rivet bolts 13 Sensor coil 14 Permanent magnet 15 vibration exciters 16 sensors 17 Bearing block 18 rolls 19 Bearing element 20 preload element 21 first section (spring area) 22 second section (free-swinging end) 23 first spring area 24 second spring area 25 Spring device 26 compression spring 27 Bearing block 28 bearing block 29 Middle position 30 pairs of bearing elements A axial direction S Oscillation direction L Longitudinal axis QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2018 / 073267 A1

[0003] DE 11 2020 002 949 T5

[0003] DE 10 2021 212 470 A1

[0003]

Claims

[1] Device (1) for determining the position of a steering rod (2) for a steering unit, in particular a steer-by-wire steering unit, of a vehicle, the device (1) comprising: an oscillating body (4) with a first axial end (8) and a second axial end (10), wherein the first axial end (8) is adapted to be fixed to a body-mounted component (3), and the second axial end (10) is adapted to be free, a coupling unit (5) for attachment to the handlebar (2), wherein the coupling unit (5) has at least one bearing element (19) for supporting the oscillating body (4) and is arranged to be axially displaceable relative to the oscillating body (4), and a sensor device (6) for determining the position of the handlebar (2), which is designed to detect an oscillation frequency of the oscillating body (4). [2] Device (1) according to claim 1, further comprising a vibration exciter (15) which is configured to excite the vibrating body (4) to vibrate. [3] Device (1) according to claim 2, wherein the vibration exciter (15) is designed as an actuator. [4] Device (1) according to one of claims 1 to 3, further comprising an oscillating mass (11) arranged at the second axial end (10) of the oscillating body (4). [5] Device (1) according to one of claims 1 to 4, wherein the sensor device (6) contains a sensor coil (13) which is adapted to detect the oscillation frequency at the second axial end (10). [6] Device (1) according to one of claims 1 to 5, further comprising a prestressing element (20) which is designed to prestress the oscillating body (4) in such a way that a coupling between the at least one bearing element (19) of the coupling unit (5) and the oscillating body (4) is ensured. [7] Device (1) according to one of claims 1 to 6, wherein the oscillating body (4) is designed as a leaf spring (7) [8] Device according to one of claims 1 to 7, wherein the coupling unit (5) has a plurality of bearing elements (19) which are arranged on both sides of the oscillating body (4) as seen in a direction of oscillation (S) of the oscillating body (4). [9] Device (1) according to one of claims 1 to 8, wherein the bearing elements (19) are designed as rollers (18) or as sliding sections. [10] Steering unit, in particular steer-by-wire steering unit, for a vehicle, comprising: a steering rod (2) which is adapted to be coupled at each of its axial ends to a wheel of a vehicle, a control actuator coupled to the steering rod (2) such that a rotational movement of the control actuator causes a translational movement of the steering rod (2), a device (1) according to one of the preceding claims, wherein the coupling unit (5) is attached to the handlebar (2), wherein the at least one bearing element (19) of the coupling unit (5) is axially displaceable by the translational movement of the handlebar (2) relative to the oscillating body (4), and wherein the sensor device (6) for determining the position of the handlebar (2) is designed to detect the oscillation frequency of the oscillating body (4). [11] Steering unit according to claim 10, further comprising an evaluation unit which is configured to determine a position of the handlebar (2) based on the oscillation frequency detected by the sensor device (6). [12] Use of a device (1) according to one of claims 1 to 9 in a steering unit, in particular a steer-by-wire steering unit, of a vehicle for determining the position of the handlebar (2), wherein the position of the handlebar (2) is determined based on the oscillation frequency detected by the sensor device (6).

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