Steering device and method for ascertaining absolute position of steering adjustment element of steering device

Abstract

The invention relates to a steering device, comprising at least one steering adjustment element (10a, 10b); an adjustment mechanism (12a, 12b) interacting with the steering adjustment element (10a, 10b), comprising at least one adjustment actuator (14a, 14b), at least one spindle drive (16a, 16b) operatively connected to the steering adjustment element (10a, 10b), and a traction tool transmission (18a, 18b) having at least one traction tool (20a, 20b) for coupling of the adjustment actuator (14a, 14b) to the spindle drive (16a, 16b); the position sensor unit (22a; 22b), which comprises a position sensor unit (14a; 14b), which is assigned to the adjustment actuator (14a; 24b) of the at least one first position sensing device (24a; 24b) associated with the screw drive (16a; 16b), and at least one second position sensing device (26a; 26b) for detecting a position of the adjustment actuator (14a; 14b), and a second position sensing device (14a; 14b) for detecting first position information of the screw drive (16a; 16b), and a position determination unit (28a; 28b), which is designed to determine a position of the steering adjustment element (10a; 10a ') at least as a function of the first position information and the second position information. 10b) of the sensor (10).

Description

Technical Field

[0001] The present invention relates to a steering device. The present invention also relates to a steering system having such a steering device, a vehicle having such a steering system, and a method for determining the absolute position of a steering adjustment element of such a steering device. Background Art

[0002] Vehicles with conventional steering systems are known from the prior art, in which the steering wheel is firmly mechanically connected to the steering gear via a steering column. The absolute position of the steering control element of the steering gear, which is usually designed as a rack in passenger cars, is determined using an additional external sensor, such as a steering angle sensor attached to the steering wheel shaft.

[0003] Furthermore, vehicles with steer-by-wire systems are known that operate without a direct mechanical connection between the steering wheel and the steered wheels, and in which the steering setting is transmitted solely electrically. Due to the missing mechanical connection, the aforementioned sensors are no longer present in the area of ​​the steering wheel shaft, so other approaches must be used to determine the absolute position of the steering control element. The absolute position of the steering control element is required, for example, to adjust its position and thereby set the correct direction of travel.

[0004] In this respect, DE 198 34 870 A1 and DE 10 2017 217 581 A1, for example, describe steering systems which, in addition to a rotor position sensor, also include an additional position sensor for determining the absolute position of a steering actuating element. Summary of the Invention

[0005] The present invention is based on the object of providing a steering device and a method for determining the absolute position of a steering actuating element, which have improved functionality, in particular in steering systems with a spindle drive. This object is achieved by the features of claims 1, 14, 15, and 16, while advantageous embodiments and developments of the invention can be found in the dependent claims.

[0006] A steering system is proposed, comprising: at least one steering adjustment element; an adjustment mechanism cooperating with the steering adjustment element, the adjustment mechanism comprising at least one adjustment actuator, at least one spindle drive operatively connected to the steering adjustment element, and a traction mechanism transmission with at least one traction mechanism for coupling the adjustment actuator to the spindle drive; a position sensor unit comprising at least one first position sensor associated with the adjustment actuator and at least one second position sensor associated with the spindle drive, the first position sensor for detecting first position information of the adjustment actuator and the second position sensor for detecting second position information of the spindle drive; and a position determination unit configured to determine the absolute position of the steering adjustment element based on at least the first and second position information. This design allows for improved determination of the absolute position of the steering adjustment element, particularly in steering systems with a spindle drive, more specifically in conventional steering systems, but also in steer-by-wire systems. Furthermore, efficiency, particularly in terms of installation space, components, maintenance, and / or cost efficiency, can be advantageously improved.

[0007] In this context, a "steering device" should be understood to mean at least a portion, such as a subassembly, of a steering system, particularly of a vehicle, preferably a motor vehicle. Advantageously, the steering system is designed as a steer-by-wire system and includes an operating unit, particularly operable by the driver and / or passenger, and at least one wheel steering angle adjuster mechanically separated from the operating unit. The wheel steering angle adjuster particularly comprises a steering adjustment element and an adjustment mechanism and is configured to vary the steering angle of at least one wheel according to a steering presetting at the operating unit. In this case, the steering device is therefore particularly a part of the wheel steering angle adjuster. The steering adjustment element is particularly axially mounted and can be configured as an output shaft (as used, for example, in commercial vehicles) and / or as a rack (as used, for example, in passenger cars). Furthermore, the adjustment mechanism is particularly configured to adjust the steering adjustment element in the axial direction. The steering adjustment element is preferably configured to cooperate with the adjustment mechanism to adjust the steering angle of at least one wheel and, thus, is particularly configured to directly influence the direction of travel. The adjustment actuator is preferably designed as an electric motor, advantageously as a brushless motor and particularly advantageously as an asynchronous motor or a permanently excited synchronous motor, and is provided to generate and / or provide a steering torque. The spindle drive can be designed, for example, as a trapezoidal screw drive or the like. However, it is preferred that the spindle drive be designed as a ball screw drive. Furthermore, the traction element drive is preferably designed as a force-locking and / or form-locking traction element drive, particularly preferably as a belt drive. In this case, the traction element can be designed as a belt, preferably as a toothed belt.

[0008] Furthermore, a "position sensor unit" should be understood in particular to mean a sensor unit that is configured to detect at least a position change of the adjusting actuator and a position change of the spindle drive. To this end, the position sensor unit includes a first position sensor device configured to preferably contactlessly detect first position information related to a position change of the adjusting actuator, in particular a motor shaft of the adjusting actuator, and a second position sensor device configured to preferably contactlessly detect second position information related to a position change of the spindle drive, in particular a spindle nut of the spindle drive. The first position sensor device is preferably arranged on the output side of the adjusting actuator, while the second position sensor device is arranged on the drive side of the spindle drive. In this case, the first and second position sensor devices are advantageously linked to each other via the traction mechanism transmission such that the absolute position of the steering adjustment element, or the position of the steering adjustment element over multiple rotations, can be unambiguously determined by linking and evaluating the first and second position information. A "position determining unit" should be understood in particular to mean an electrical and / or electronic unit having an information input, information processing, and information output. Advantageously, the position determination unit also comprises at least one processor, at least one operating memory, at least one input and / or output means, and / or at least one operating program. In particular, the position determination unit is configured at least to clearly determine the absolute position of the steering adjustment element or the position of the steering adjustment element over a plurality of rotations by evaluating the first position information and the second position information. Preferably, the position determination unit is integrated into a control unit of the vehicle, for example a central vehicle control unit or a control unit of the steering system, in particular in the form of a steering control unit. "Configured" should be understood in particular to mean specially programmed, designed, and / or equipped. "An object configured for a specific function" should be understood in particular to mean that the object fulfills and / or implements this specific function in at least one application state and / or operating state.

[0009] Furthermore, it is proposed that the first position sensor device includes at least one angle sensor and is configured to detect angle information of the adjusting actuator, advantageously the angular state and / or angular position of the motor shaft of the adjusting actuator. In this case, the first position information thus corresponds to the angle information of the adjusting actuator. Preferably, the first position sensor device has a maximum measuring range of 360°, i.e., a measuring range of 0° to 360°. In this regard, the first position sensor device can be configured, for example, as a single-turn sensor or include at least one, advantageously exactly one, single-turn sensor. This makes it particularly easy and cost-effective to detect the first position information and advantageously determine the absolute position of the steering adjusting element.

[0010] According to a preferred embodiment, it is further proposed that the second position sensor device includes at least one further angle sensor and is configured to detect further angular information of the spindle drive, advantageously the angular state and / or angular position of the spindle nut of the spindle drive. In this case, the second position information thus corresponds to the angular information of the spindle drive. Preferably, the second position sensor device in this case has a maximum measuring range of 360°, i.e., a measuring range of 0° to 360°. In this regard, the second position sensor device can be configured, for example, as a single-turn sensor or include at least one, advantageously exactly one, single-turn sensor. This makes it particularly easy and cost-effective to detect the second position information and advantageously determine the absolute position of the steering adjustment element.

[0011] Alternatively, however, the second position sensor can also include at least one marking sensor and be configured to detect marking information from the screw drive. The marking information can correspond, for example, to a single pulse or multiple pulses per rotation of the screw drive. This makes it possible to advantageously and efficiently determine the second position information.

[0012] Furthermore, it is proposed that the first and second position sensor devices have the same measuring principle for detecting the corresponding position information. In this context, the term "measuring principle" is to be understood in particular to mean the measuring method used to detect the corresponding position information, such as, for example, a magnetic, inductive, optical, capacitive, mechanical, and / or piezoelectric measuring method, and / or the type of measuring sensor device used, in particular the type of sensor used. Preferably, the first and second position sensor devices are each configured to detect the corresponding position information magnetically. Particularly preferably, the first and second position sensor devices are also designed to be structurally identical. This makes it possible, in particular, to achieve a correlation between the first and second position sensor devices that is advantageously and easily assessable.

[0013] Furthermore, it is proposed that the first position information is a first detection signal having a first periodicity, and the second position information is a second detection signal having a second periodicity different from the first periodicity. Preferably, in particular, the first meshing element of the adjustment actuator coupled to the traction tool and in particular the second meshing element of the screw drive coupled to the traction tool can have different numbers of teeth in this respect in order to generate and / or cause detection signals with different periodicities. Preferably, the number of teeth of the first meshing element is smaller than the number of teeth of the second meshing element. Particularly preferably, the number of teeth of the second meshing element is at least twice the number of teeth of the first meshing element. This makes it possible to provide detection signals with different periodicities in an advantageously simple manner.

[0014] If the position determining unit is configured to use a non-vernier approach to determine the absolute position of the steering adjusting element, a particularly easy correlation between the first position sensor device and the second position sensor device and thus an easy determination of the absolute position of the steering adjusting element can also be achieved.

[0015] According to another embodiment, the position sensor unit includes at least one third position sensor device assigned to the traction tool transmission, which is used to detect third position information of the traction tool, and the position determination unit is configured to take into account the third position information, particularly in the axial direction, when determining the absolute position of the steering adjustment element. Therefore, the position sensor unit can also be configured to detect changes in the position of the traction tool. To this end, the position sensor unit can include a third position sensor device configured to detect, preferably contactlessly, correlated third position information related to changes in the position of the traction tool. In particular, the first, second, and third position sensors are correlated with one another in this case so that the absolute position of the steering adjustment element, or the position of the steering adjustment element over multiple rotations, can be unambiguously determined by correlating and evaluating the first, second, and third position information. Furthermore, the position determination unit is particularly configured to unambiguously determine the absolute position of the steering adjustment element, or the position of the steering adjustment element over multiple rotations, by evaluating the first, second, and third position information. This further improves the determination of the absolute position of the steering adjustment element. In particular, the unambiguity of the absolute position of the steering adjusting element can be increased by extending the measurement into the third dimension.

[0016] Furthermore, it is proposed that the third position sensor device has a different measurement principle for detecting the third position information than the first and / or second position sensor device. In particular, the third position sensor device can use different measurement methods, such as inductive and / or optical measurement methods and / or different sensor types, to detect the third position information. This can further increase the accuracy of determining the absolute position of the steering actuating element.

[0017] According to another embodiment, the third position sensor device includes at least one position sensor and is configured to detect rotational position information of the traction tool. In particular, the third position sensor device can be configured to scan the traction tool substantially continuously, thereby enabling the precise and / or current rotational position of the traction tool to be determined. This makes it possible to advantageously and precisely determine the rotational position of the traction tool.

[0018] According to an alternative design, the third position sensor includes at least one marking sensor and is configured to detect marking information of the traction tool. The marking information can correspond, for example, to a single pulse or multiple pulses per rotation of the traction tool. This makes it possible to advantageously and efficiently determine the rotational position of the traction tool.

[0019] Furthermore, a method for determining the absolute position of a steering adjustment element of the aforementioned steering device is proposed. In this method, at least first position information of an adjustment actuator and second position information of a spindle drive are correlated with one another and evaluated to unambiguously determine the position, in particular the absolute position, of the steering adjustment element. In particular, a position determination unit is configured to execute the method for determining the absolute position of the steering adjustment element. This enables, in particular, the advantages already mentioned above to be achieved.

[0020] The steering device, the steering system, the vehicle, and the method for determining the absolute position of a steering adjusting element are not intended to be limited to the applications and embodiments described above. In particular, the steering device, the steering system, the vehicle, and the method for determining the absolute position of a steering adjusting element can have a different number of individual elements, components, and units than those mentioned here in order to fulfill the functional mode described here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further advantages are obtained from the following description of the drawings. In the drawings, two exemplary embodiments of the invention are shown.

[0022] in: Figure 1 A schematic diagram shows a vehicle having a steering system designed as a steer-by-wire system, which includes a steering device, Figure 2 A detailed illustration shows a steering control element, an adjustment mechanism, a position sensor unit and a position determining unit of a steering device. Figure 3 An exemplary diagram of a detection signal of a first position sensor device of a position sensor unit and a second detection signal of a second position sensor device of the position sensor unit is shown in a common xy diagram, Figure 4 An exemplary flow chart of the main method steps of a method for determining the absolute position of a steering adjusting element is shown, and Figure 5 A further exemplary embodiment of a steering adjustment element, an adjustment mechanism, a position sensor unit and a position determining unit of a further steering device is shown in a detailed illustration. DETAILED DESCRIPTION

[0023] Figure 1A simplified diagram shows a vehicle 34a, exemplarily designed as a passenger car, having a plurality of wheels (not shown) and a steering system 32a. Steering system 32a is operatively connected to the wheels and is provided for influencing the direction of travel of vehicle 34a. Furthermore, steering system 32a is currently designed as a steer-by-wire system and includes an operating unit 36a with a steering handle (not shown), operable, in particular, by the driver and / or passenger, and a wheel steering angle adjuster 38a mechanically decoupled from operating unit 36a and connected, in particular, to the wheels. Vehicle 34a also includes a controller 40a with a computing unit (not shown). Controller 40a is currently designed as a steering controller and is therefore part of steering system 32a. Controller 40a is electrically connected to operating unit 36a and to wheel steering angle adjuster 38a. Controller 40a thus couples operating unit 36a to wheel steering angle adjuster 38a and controls the operation of steering system 32a. In principle, the controller can also be designed differently from the steering controller and, for example, as a separate central vehicle controller with a central processing unit. Furthermore, it is conceivable to provide separate controllers for the wheel steering angle adjusters and the operating unit and to connect them to each other in a communicative manner. Furthermore, the steering system can be designed as a conventional steering system, in particular as an electric servo steering system.

[0024] Figure 2 A part of the wheel steering angle adjuster 38a is shown in a detailed illustration. The wheel steering angle adjuster 38a has a steering device.

[0025] The steering system includes a steering control element 10a, exemplarily designed as a rack. The steering control element 10a is mounted movably in the axial direction and is provided for converting a steering specification, such as that at the operating unit 36a, into a steering movement of the wheels. To this end, the steering control element 10a currently has a total travel of approximately + / - 110 mm.

[0026] Furthermore, the steering device comprises an adjusting mechanism 12 a coupled to the steering adjusting element 10 a for adjusting the steering adjusting element 10 a in the axial direction.

[0027] The adjusting mechanism 12a includes an adjusting actuator 14a. The adjusting actuator 14a is currently designed as an electric motor, in particular as a brushless motor and preferably as a permanently excited synchronous motor. The adjusting actuator 14a is designed as a rotary motor and includes a motor shaft 42a, which is particularly rotatably supported and defines the axis of rotation of the adjusting actuator 14a. Furthermore, the adjusting actuator 14a currently includes a first toothing element 44a in the form of a pinion, coupled to the motor shaft 42a and / or designed integrally therewith. The first toothing element 44a has, by way of example, 41 teeth. However, in principle, the adjusting actuator can also include multiple electric motors. Furthermore, the first toothing element can have a different number of teeth.

[0028] Furthermore, the adjustment mechanism 12a includes a spindle drive 16a, which is currently configured as a ball screw drive. The spindle drive 16a is arranged on the steering adjustment element 10a and is directly connected thereto. The spindle drive 16a includes a spindle nut 46a, which is particularly rotatably supported and is in the form of a ball nut. Furthermore, the spindle drive 16a currently includes a second toothing element 48a, which is in the form of a pinion and / or is configured integrally with the spindle nut 46a. The second toothing element 48a has, by way of example, 117 teeth. Therefore, the number of teeth of the first toothing element 44a is currently smaller than that of the second toothing element 48a. However, in principle, the second toothing element can also have a different number of teeth.

[0029] Furthermore, the adjustment mechanism 12a includes a traction element transmission 18a, in this case, specifically a belt drive, which is used to adjust the coupling between the actuator 14a and the spindle drive 16a. To this end, the traction element transmission 18a includes at least one traction element 20a. In this case, the traction element 20a is configured as a belt, more specifically, a toothed belt having, for example, 155 teeth, and is wound around the first toothed element 44a and the second toothed element 48a. The traction element transmission 18a is configured to transmit the adjustment torque or motor torque of the adjustment actuator 14a to the spindle drive 16a, thereby causing the steering adjustment element 10a to move in the axial direction. A complete displacement stroke of the steering adjustment element 10a requires multiple rotations of the adjustment actuator 14a and the spindle drive 16a. Alternatively, the traction element in the form of a toothed belt can also have a different number of teeth. Furthermore, the traction element transmission can also be configured as a chain drive, etc.

[0030] The steering device also includes a position sensor unit 22a. In the present embodiment, the position sensor unit 22a is configured to detect position changes of the adjusting actuator 14a, in particular the motor shaft 42a, and of the spindle drive 16a, in particular the spindle nut 46a. To this end, the position sensor unit 22a includes a first position sensor device 24a and a second position sensor device 26a.

[0031] A first position sensor 24a is associated with the adjusting actuator 14a. The first position sensor 24a is arranged in the axial end region of the adjusting actuator 14a, in particular, of the motor shaft 42a. The first position sensor 24a is arranged on the output side of the adjusting actuator 14a. Furthermore, the first position sensor 24a is configured as an angle sensor and includes at least one angle sensor, for example, in the form of a magnetoresistive angle sensor. In this embodiment, the first position sensor 24a is configured as a single-turn sensor and has a maximum measuring range of 360°. The first position sensor 24a is configured to contactlessly detect first position information. In this embodiment, the first position sensor 24a is configured to magnetically detect the first position information. The first position sensor 24a is configured to detect the angular state and / or angular position of the adjusting actuator 14a, in particular, of the motor shaft 42a, and to provide this as a first detection signal. The first detection signal has a first periodicity. Alternatively, however, the first position sensor may also include multiple magnetoresistive angle sensors and / or GMR or TMR measuring elements. Furthermore, the first position sensor can use measuring methods other than magnetic measuring methods, such as optical and / or inductive measuring methods. In principle, it is also conceivable to arrange the first position sensor in a region of the actuating actuator other than the axial end region.

[0032] A second position sensor 26a is assigned to the screw drive 16a. It is arranged in an axial end region of the screw drive 16a. It is located on the drive side of the screw drive 16a. Furthermore, the second position sensor 26a is currently configured as an angle sensor and includes at least one additional angle sensor, for example, in the form of a magnetoresistive angle sensor. It is currently configured as a single-turn sensor and has a maximum measuring range of 360°. The second position sensor 26a is configured to contactlessly detect second position information. Currently, the second position sensor 26a is configured to magnetically detect the second position information. The second position sensor 26a is configured to detect the angular state and / or angular position of the screw drive 16a, in particular the spindle nut 46a, and to provide this as a second detection signal. The second detection signal has a second periodicity that is different from the first periodicity of the first detection signal. Therefore, the first and second position sensors 24a, 26a employ the same measurement principle for detecting the respective position information. However, as an alternative, the second position sensor device can also include multiple magnetoresistive angle sensors and / or GMR or TMR measuring elements. Furthermore, the second position sensor device can use measurement methods other than magnetic measurement methods, such as optical and / or inductive measurement methods. Furthermore, the second position sensor device can alternatively include at least one marking sensor and be configured to detect marking information of the screw drive. The marking information can, for example, correspond to a single pulse or multiple pulses per rotation of the screw drive. Furthermore, it is generally conceivable that the second position sensor device is arranged in an area of ​​the screw drive that is different from the axial end area.

[0033] The steering device also includes a position determination unit 28a. Position determination unit 28a is currently integrated into control unit 40a and has an electrical connection to a computing unit. Position determination unit 28a also has an electrical connection to position sensor unit 22a, in particular, first position sensor device 24a and second position sensor device 26a. Position determination unit 28a includes at least one processor (not shown), for example, in the form of a microprocessor, and at least one operating memory (not shown). Position determination unit 28a also includes at least one operating program stored in the operating memory, including determination and evaluation routines. Position determination unit 28a is configured to determine the absolute position of steering control element 10a based on first and second position information. Currently, position determination unit 28a is configured to use a vernier approach or the non-Prinzip principle and to unambiguously determine the absolute position of steering control element 10a, or the position of steering control element 10a over multiple rotations, by evaluating first position information, in particular a first detection signal, and second position information, in particular a second detection signal. Here, it is utilized that the first position sensor device 24a and the second position sensor device 26a are linked to each other via the traction tool transmission device 18a in such a way that by linking and evaluating the first position information or the first detection signal with a first periodicity with the second position information or the second detection signal with a second periodicity, the absolute position of the steering adjustment element 10a or the position of the steering adjustment element 10a within a plurality of rotations can be clearly determined.

[0034] Figure 3 An exemplary diagram is shown, in which a first piece of position information detected by first position sensor device 24a and a second piece of position information detected by second position sensor device 26a are plotted in a common xy diagram.

[0035] The abscissa axis 50a is designed as a dimension axis and shows a first piece of position information, in this case, in particular, an angular state and / or an angular position of the adjusting actuator 14a in an angular range between 0° and 360° or between 0 and 1. The ordinate axis 52a is designed as a further dimension axis and shows a second piece of position information, in this case, in particular, an angular state and / or an angular position of the spindle drive 16a in an angular range between 0° and 360° or between 0 and 1.

[0036] The total displacement travel of the deflection adjustment element 10 a is + / −110 mm at a thread pitch of 7 mm per turn. Figure 3 The individual lines in the traction means transmission 18a are straight lines, which are all parallel to each other. Each position of the steering adjustment element 10a corresponds to Figure 3Thus, the absolute position of the steering adjustment element 10a or the position of the steering adjustment element 10a over a plurality of rotations can be determined by evaluating the first position information and the second position information when using a vernier concept or the vernier principle.

[0037] Figure 4 An exemplary flow chart of the main method steps of a method for determining the absolute position of a steering adjusting element 10a is shown. In the present case, in particular, a position determining unit 28a, optionally in cooperation with a computing unit, is provided for carrying out the method and for this purpose comprises a computer program with corresponding program code sections.

[0038] In a first method step 60a, first and second position information are determined. To this end, the first position information is detected by means of first position sensor device 24a and transmitted to position determination unit 28a. Furthermore, the second position information is detected by means of second position sensor device 26a and transmitted to position determination unit 28a.

[0039] In a second method step 62a, the absolute position of the steering adjusting element 10a is determined. To this end, the first position information and the second position information are correlated with one another and evaluated in order to unambiguously determine the position of the steering adjusting element 10a, in particular by means of a vernier approach.

[0040] Figure 4 The exemplary flow chart in FIG. 1 is intended to merely illustrate a method for determining the absolute position of the steering adjustment element 10a. In particular, individual method steps can be modified or additional method steps can be added. In the first method step 60a, for example, third position information of the traction mechanism transmission 18a can be determined using a third position sensor device and transmitted to the position determination unit 28a. Furthermore, the third position information can be taken into account when determining the absolute position of the steering adjustment element 10a in the second method step 62a.

[0041] exist Figure 5 The following description and drawings are essentially limited to the differences between the exemplary embodiments, wherein, for identically designated components, in particular for components with the same reference numerals, reference can in principle also be made to the other exemplary embodiments, in particular Figures 1 to 4 In order to distinguish the embodiments, Figures 1 to 4 The reference numerals of the embodiments in the embodiment are followed by the letter a. Figure 5 In the embodiment, the letter a is replaced by the letter b.

[0042] Figure 5The further exemplary embodiment of differs from the preceding exemplary embodiment at least essentially in the design of the position sensor unit 22 b of the steering device.

[0043] In this case, the position sensor unit 22b is configured to detect changes in position of the adjustment actuator 14b of the adjustment mechanism 12b, changes in position of the spindle drive 16b of the adjustment mechanism 12b, and changes in position of the traction tool 20b of the traction tool drive 18b of the adjustment mechanism 12b, in particular in the form of a belt drive. To this end, the position sensor unit 22b includes a first position sensor device 24b, a second position sensor device 26b, and a third position sensor device 30b.

[0044] The first position sensor device 24b is associated with the adjusting actuator 14b and is provided to detect first position information of the adjusting actuator 14b. The first position sensor device 24b corresponds to the first position sensor device 24a of the previous exemplary embodiment.

[0045] The second position sensor device 26b is associated with the spindle drive 16b and is provided for detecting second position information of the spindle drive 16b. The second position sensor device 26b corresponds to the second position sensor device 26a of the previous exemplary embodiment.

[0046] The third position sensor 30b is assigned to the traction means transmission 18b and is configured to detect third position information of the traction means 20b. The third position sensor 30b has a different measurement principle for detecting the third position information than the first position sensor 24b and the second position sensor 26b. Currently, the third position sensor 30b includes at least one marking sensor and is configured to detect marking information of the traction means 20b. The marking information can correspond to a single pulse or multiple pulses per rotation of the traction means 20b. Alternatively, however, the third position sensor can also include at least one position sensor and be configured to detect rotational position information of the traction means. In particular, the third position sensor can be configured to scan the traction means substantially continuously in this case, thereby being able to determine the precise and / or current rotational position of the traction means.

[0047] The steering device also includes a position determining unit 28b, which is electrically connected to the position sensor unit 22b, in particular the first position sensor device 24b, the second position sensor device 26b, and the third position sensor device 30b, and is configured to determine the absolute position of the steering control element 10b of the steering device based on the first, second, and third position information. Therefore, in this case, the third position information is taken into account when determining the absolute position of the steering control element 10b. The position determining unit 28b is configured to use a vernier approach or a vernier principle and to unambiguously determine the absolute position of the steering control element 10b, or the position of the steering control element 10b over a plurality of rotations, by evaluating the first, second, and third position information. Here, it is utilized that the first position sensor device 24b, the second position sensor device 26b and the third position sensor device 30b are linked to one another in such a way that the absolute position of the steering adjustment element 10b or the position of the steering adjustment element 10b over a plurality of rotations can be clearly ascertained by linking and evaluating the first position information, the second position information and the third position information. Figure 3 In a common xyz diagram, the first position information detected by the first position sensor device 24b, the second position information detected by the second position sensor device 26b, and the third position information detected by the third position sensor device 30b are plotted. By extending the measurement into the third dimension, the clarity of the absolute position of the steering adjustment element 10b can be increased due to the greater spacing between the straight lines.

Claims

1. A steering device comprising: at least one steering adjustment element (10a; 10b); an adjusting mechanism (12a; 12b) cooperating with the steering adjusting element (10a; 10b), the adjusting mechanism comprising at least one adjusting actuator (14a; 14b), at least one screw drive (16a; 16b) operatively connected to the steering adjusting element (10a; 10b), and a traction tool transmission (18a; 18b) with at least one traction tool (20a; 20b) for coupling the adjusting actuator (14a; 14b) to the screw drive (16a; 16b); a position sensor unit (22a; 22b), comprising at least one first position sensor device (24a; 24b) assigned to the adjusting actuator (14a; 14b) and at least one second position sensor device (26a; 26b) assigned to the screw drive (16a; 16b), the first position sensor device being used to detect first position information of the adjusting actuator (14a; 14b), and the second position sensor device being used to detect second position information of the screw drive (16a; 16b); and A position determining unit (28a; 28b) is provided for determining the absolute position of the steering adjustment element (10a; 10b) at least based on the first position information and the second position information.

2. The steering device according to claim 1, characterized in that The first position sensor device (24a; 24b) comprises at least one angle sensor and is configured to detect angle information of the adjusting actuator (14a; 14b).

3. The steering device according to claim 2, characterized in that The first position sensor device (24a; 24b) has a maximum measuring range of 360°.

4. Steering device according to any one of the preceding claims, characterized in that The second position sensor device (26a; 26b) comprises at least one further angle sensor and is provided for detecting further angle information of the spindle drive (16a; 16b).

5. The steering device according to claim 4, characterized in that The second position sensor device (26a; 26b) has a maximum measuring range of 360°.

6. The steering device according to any one of claims 1 to 3, characterized in that The second position sensing device (26a; 26b) includes at least one marking sensor and is configured to detect marking information of the screw drive (16a; 16b).

7. Steering device according to any one of the preceding claims, characterized in that The first position sensor device (24a; 24b) and the second position sensor device (26a; 26b) have the same measuring principle for detecting corresponding position information.

8. Steering device according to any one of the preceding claims, characterized in that The first position information is a first detection signal having a first periodicity, and the second position information is a second detection signal having a second periodicity different from the first periodicity.

9. Steering device according to any one of the preceding claims, characterized in that The position determining unit (28a; 28b) is configured to use a vernier approach to determine the absolute position of the steering adjustment element (10a; 10b).

10. Steering device according to any one of the preceding claims, characterized in that The position sensor unit (22b) includes at least one third position sensor device (30b) assigned to the traction tool transmission (18b), which is used to detect third position information of the traction tool (20b), and the position determination unit (28b) is configured to take the third position information into account when determining the absolute position of the steering adjustment element (10b).

11. The steering device according to claim 10, characterized in that The third position sensor device (30b) has a different measuring principle for detecting the third position information than the first position sensor device (24b) and / or the second position sensor device (26b).

12. The steering device according to claim 10 or 11, characterized in that The third position sensing device (30b) includes at least one position sensor and is configured to detect rotational position information of the traction tool (20b).

13. The steering device according to claim 10 or 11, characterized in that The third position sensor device (30b) includes at least one marking sensor and is configured to detect marking information of the traction tool (20b).

14. A steering system (32a), in particular a steer-by-wire system, comprising at least one steering device according to any one of the preceding claims.

15. A vehicle (34a) having a steering system (32a) according to claim 14.

16. A method for ascertaining the absolute position of a steering adjustment element (10a; 10b) of a steering device according to any one of claims 1 to 13, in which method at least first position information of the adjustment actuator (14a; 14b) and second position information of the spindle drive (16a; 16b) are linked to one another and evaluated in order to unambiguously determine the position of the steering adjustment element (10a; 10b).

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