Steering device for a motor vehicle with a split steering shaft and steer-by-wire steering system with such a steering device

Abstract

The invention relates to a steering device (1) for a motor vehicle, comprising a stationary first brake part (16) and a steering shaft. The steering shaft is rotatably mounted and comprises a first steering shaft section (2) and a second steering shaft section (3). A profiled disc (6, 7) is attached to each of the steering shaft sections (2, 3), which generates a braking force with respect to the steering shaft when there is a speed difference between the two steering shaft sections (2, 3). Furthermore, the invention relates to a steer-by-wire steering system having such a steering device.

Description

[0001] The invention relates to a steering device for a motor vehicle with a stationary first brake part and a steering shaft. The steering shaft is mounted for rotation about its central longitudinal axis, the steering shaft having a first steering shaft section, and the steering shaft having a second steering shaft section with a second brake part arranged thereon. The second brake part is pressed against the stationary brake part when a braking force is applied. Furthermore, the invention relates to a steer-by-wire steering system with such a steering device.

[0002] Such a steering device with additional braking of the steering handle is known, for example, from DE 10 2023 202 440 A1. Here, a feedback drive with a gear is attached to a steering column. When a limit torque is exceeded, the separation forces of a bevel gear are used to press two parts of a braking device together. The first part of the braking device is attached to a gear of the bevel gear of the steering shaft. The other braking part of the braking device is fixedly mounted, and as soon as the first braking part of the steering shaft moves toward the stationary braking part, an additional braking torque is generated.

[0003] Steer-by-wire steering systems have no mechanical connection between the steering wheel and the vehicle wheels, which is why such steering systems incorporate a simulator unit to provide feedback to the driver. The simulator unit simulates the steering forces acting on the steered vehicle wheel, thereby giving the driver an impression of the steering status. For this purpose, the simulator unit incorporates a feedback drive attached to a steering shaft, which in turn is connected to the steering wheel. However, the torque that can be generated by the feedback drive is limited due to the available installation space, which is why the speed of an actuator within the feedback drive is often reduced by a gearbox. Despite the gearbox reduction, the torque that can be generated at the steering wheel is sometimes not high enough to provide a sufficiently high torque in every driving condition.

[0004] Due to the limited installation space, the use of larger actuators for the feedback drive is limited. The use of different transmissions such as gear drives or planetary gears is also limited, as these can increase torque, but at the expense of the achievable speed. The feedback drive would then no longer be able to follow rapid steering movements.

[0005] In special situations, high torques are required to brake the steering wheel against the driver's turning movement. Such driving situations can occur, for example, if a driver gets in or out of the vehicle and leans on the steering wheel, whereby a high torque is transmitted to the steering wheel. The torque provided by the feedback drive in this situation is not sufficient to hold the steering wheel in a desired position. Instead, the steering wheel would turn away while the driver gets in or out, which can lead to irritation. It is therefore necessary to be able to transmit an additional braking torque to the steering wheel.

[0006] The object of the invention is to overcome the disadvantages of the prior art, in particular to provide a steering device and / or a steer-by-wire steering system in which a high counter-torque can be provided to a steering handle, which exceeds that of the feedback drive. In particular, an alternative embodiment is to be provided in which the installation space requirement is also reduced.

[0007] The object underlying the invention is achieved by a steering device according to claim 1 and by the steer-by-wire steering system according to claim 13. Preferred developments of the invention can be found in the subclaims and in the following description.

[0008] The steering device is designed for use in a vehicle, in particular in a motor vehicle. Preferably, a vehicle has such a steering device. The steering device has a steering shaft, which can be designed to transmit the torque applied by the vehicle driver to the steering handle to a rack. The rack converts the rotational movement of the steering shaft into a translational movement, thereby changing the steering angle of the vehicle wheels. The steering shaft is mounted for rotation about its central longitudinal axis, with the steering shaft being divided into a first steering shaft section and a second steering shaft section. Preferably, it is a steer-by-wire steering system, in which there is no mechanical connection between the steering shaft and the steered vehicle wheels, and a rotation angle of the steering shaft is read, and the vehicle wheels are steered accordingly.

[0009] The steering device further comprises a stationary first brake part, which is preferably attached to a stationary housing of the steering device. However, the stationary first brake part can also be attached directly to the motor vehicle. The steering device also comprises a second brake part, which is arranged on the second steering shaft section and is pressed against the stationary brake part when a braking force is applied. In particular, it is provided that the second brake part can move along the central longitudinal axis on the second steering shaft section. If the second brake part comes into contact with the stationary first brake part, a braking effect of the steering shaft is generated.

[0010] In addition, a first profiled disc is arranged on the first steering shaft section and a second profiled disc on the second steering shaft section. If the two steering shaft sections have a different speed, the two profiled discs slide against each other and generate a braking force by pressing the second brake part onto the stationary first brake part.

[0011] It is provided that the first profiled disc is connected to the first steering shaft section, in particular, it cannot move axially or radially. In contrast, the second profiled disc is preferably axially displaceable on the second steering shaft section so that the second brake part can be pressed against the stationary first brake part. In particular, the second profiled disc is connected to the second steering shaft section in a rotationally fixed manner, for example, via a pinion shaft. The second profiled disc and the second steering shaft section can also be connected to each other via a key.

[0012] In particular, due to the torsionally rigid connection of the profiled discs to their respective steering shaft sections, the rotational speed of the respective steering shaft section corresponds to that of the profiled disc connected to it. In this embodiment, the feedback drive can be arranged coaxially with the second steering shaft section.

[0013] The advantage is that due to the friction between the brake parts of the steering device, the actuator of the feedback drive can be smaller and the required installation space is reduced.

[0014] According to a first embodiment, the first profiled disc has a first ramp profile that interacts with a complementarily designed second ramp profile of the second profiled disc. Preferably, the steering device has a rotation mode in which both ramp profiles abut one another with a maximum contact area. The entire moment of resistance at the steering handle is provided by the feedback drive, with no braking effect being generated by the brake components in the rotation mode. As the moment of resistance of the feedback drive increases, the steering device transitions from the rotation mode to a braking mode in which both profiled discs are partially lifted away from one another in the axial direction of the central longitudinal axis, thereby generating the braking force.

[0015] In particular, the resistance torque of the feedback drive causes the two profiled discs to slide against each other, resulting in the second profiled disc being displaced along the central longitudinal axis. As the second profiled disc slides off the first profiled disc, the second brake part is pressed against the stationary brake part. The resulting braking effect transmits an additional braking torque to the steering handle, which is superimposed on the resistance torque of the feedback drive.

[0016] In other words, the resistance moment of the feedback drive is increased by the steering device according to the invention by adding the braking torque of the brake parts to the resistance moment of the feedback drive.

[0017] According to a preferred embodiment, it is provided that the first profiled disc and / or the second profiled disc is connected in a rotationally fixed manner to the associated first steering shaft section or second steering shaft section, wherein the first profiled disc or the second profiled disc is arranged axially along the central longitudinal axis and displaceably relative to the associated steering shaft section.

[0018] A further advantageous embodiment provides that the first or second profile disc is pre-tensioned towards each other by means of a pre-tensioning device against lifting off in the axial direction to the central longitudinal axis, wherein the braking force is only applied after overcoming a pre-tensioning force provided by the pre-tensioning device.

[0019] The preload device preloads both profiled discs against each other and prevents them from lifting at low moments of resistance of the feedback drive. The level of the preload force can be used to adjust the resistance moment at which the braking torque of the steering device occurs. For example, a light motor vehicle may require a different preload force than a light commercial vehicle. If the resistance moment of the feedback drive exceeds the preload force, the profiled discs slide against each other, resulting in the additional braking torque.

[0020] The preload device preferably has at least one tension spring element, wherein the tension spring element is connected by a first end to the first profiled disc and by a second end facing away from the first end to the second profiled disc. The tension spring element can have a linear or non-linear spring characteristic, which leads to different characteristics of the steering device. A disproportionately increasing braking torque of the steering device can demonstrate advantages over a linear increase in selected driving conditions. Instead of a tension spring, other actuators capable of transmitting a preload force to the profiled discs can also be used, for example pneumatic, electric, or hydraulic actuators.

[0021] According to a further aspect of the invention, the second steering shaft section is connected to a feedback drive for generating a resistance moment. In particular, the feedback drive is arranged at an end of the second steering shaft section facing away from the second profiled disc. Preferably, a steering handle is arranged at an end of the first steering shaft section facing away from the first profiled disc. In particular, the steering handle is designed as a steering wheel.

[0022] The feedback drive can be connected to the second steering shaft section via a transmission to increase the torque. However, it is also possible for the feedback drive to be arranged on the first steering shaft section and the steering handle to be arranged on the second steering shaft section. Furthermore, it is possible for both the feedback drive and the steering handle to be arranged on a common steering shaft section.

[0023] Preferably, the braking torque on the steering handle between the first and second brake parts is proportional to the resistance torque of the feedback drive. It has proven advantageous to use the resistance torque of the feedback drive as a control variable for the braking torque that can be generated by the steering device. This allows a very large total braking torque to be generated with just one actuator with a low torque. If the resistance torque increases, the profiled discs separate further from each other, and the braking torque increases.

[0024] In particular, it is further provided that the resistance torque of the feedback drive and the braking torque of the steering device are superimposed to form a total braking torque. As already described above, the braking torque of the steering device can be varied, in particular by adjusting the pretensioning device and / or the geometric dimensions of the profiled disc.

[0025] According to a further development, at least one rolling element is arranged between the two profiled discs, which is rotationally symmetrical to reduce friction between the profiled discs. In order for the profiled discs to slide against each other, friction must be overcome. Rolling elements such as balls or cylinders can be used to reduce friction between the profiled discs. This results in faster response of the steering system and more sensitive control of the overall braking torque.

[0026] According to a further embodiment, the first ramp profile and the second ramp profile each have a plurality of ring segments, wherein each ring segment has a ramp surface and the ramp surfaces rise from a first end of a ring segment to a second end of the same ring segment in the axial direction as seen from the central longitudinal axis, and first ends of immediately adjacent ring segments and second ends of immediately adjacent ring segments abut one another and / or merge into one another. In other words, the ramp profile is undulating or wave-like, wherein the number of waves is between 1 and 3, preferably between 3 and 7 waves. The axial distance along the central longitudinal axis between the wave trough and the wave crest is dimensioned such that the second brake part bears against the stationary brake part in between. This prevents the steering device from "spinning".Together with the preload device, the ramp profile can be used to adjust the characteristics of the steering system. A steep ramp profile, for example, produces an aggressive increase in braking torque.

[0027] A further advantageous embodiment provides that the steering device has a torsion bar, wherein a first part of the torsion bar is attached to the first steering shaft section and a second part of the torsion bar is attached to the second steering shaft section. In this case, a central longitudinal axis of the torsion bar coincides with the central longitudinal axis of the steering shaft. To accommodate the torsion bar, the steering shaft is preferably hollow. The torsion bar applies additional torque to the steering handle, and lifting of the profiled discs can be adjusted more sensitively. The length of the torsion bar and its diameter allow the braking torque to be further regulated and thus adapted to different vehicles.

[0028] It is further provided that the first steering shaft section or the second steering shaft section is rotatable about the central longitudinal axis due to a torsional play with the associated first or second profiled disc. Only after the torsional play has been overcome does the first or second profiled disc abut against a stop device of the associated steering shaft section. As a result, only after the torsional play has been overcome are the profiled discs lifted away from one another and a braking force generated. For this purpose, the first or second profiled disc is no longer connected to the steering shaft section in a rotationally fixed manner, but has a certain amount of play in the circumferential direction. If the steering shaft section is moved beyond the torsional play, a steering shaft stop abuts a profiled disc stop and the profiled disc is carried along with the steering shaft section, provided the direction of movement does not change.

[0029] The torsional play allows the steering handle to be rotated around a center position, which allows the steering characteristics to be adjusted and provides an additional option for adaptation to different vehicles. This is preferably combined with the torsion bar.

[0030] According to a further embodiment, the steering device comprises a further brake part, which is arranged rotationally fixed relative to the central longitudinal axis of the steering shaft. Furthermore, the steering device comprises an actuating mechanism, which, in a first mode, generates a braking effect on the steering shaft. In this first mode, the further brake part is pressed against the second brake part by means of the actuating mechanism. For example, it can be provided that the actuating mechanism and the further brake part are arranged in the stationary housing of the steering device, with the further brake part being displaceable axially along the central longitudinal axis.

[0031] If the actuating mechanism is activated, it can press the additional brake component against the second brake component of the second profiled disc, thereby generating an additional braking torque. This additional braking torque is superimposed on the resistance torque of the feedback drive and the braking torque of the steering device. In particular, it is intended that this additional braking torque is used in a situation in which the feedback drive fails. This ensures that at least a small braking torque is applied to the steering handle, thus allowing the driver to feel a minimum braking torque.

[0032] Preferably, in a second mode of the actuating mechanism, the additional brake part is moved into a released position by the second brake part. This allows the additional braking torque to be controlled using the actuating mechanism, with continuous control being particularly possible. According to a preferred embodiment, the actuating mechanism is an electromechanical actuator, and the first mode is triggered when the actuating mechanism is de-energized.

[0033] If, for example, the power supply within the vehicle fails, at least the electromechanical actuating mechanism is capable of generating an additional braking torque on the vehicle's steering handle in the first mode. For this purpose, the electromechanical actuating mechanism can have a coil and an associated core, with the core preloaded by a spring. If the power supply fails, the energy stored in the spring can be released, and the additional brake component is pressed against the second brake component.

[0034] A steer-by-wire steering system with a steering device according to the invention is particularly advantageous. The steer-by-wire steering system is preferably developed according to the embodiment explained in connection with the steering device according to the invention described here. For this purpose, the braking device can be used to provide a steering stop that prevents the steering shaft from twisting beyond a defined range. The steering stops are preferably variable depending on the driving and / or stationary situation of the vehicle.

[0035] The invention is explained in more detail below with reference to the figures. Like reference numerals refer to like, similar, or functionally identical components or elements. They show: Fig. 1: a schematic first side view of a first steering device according to the invention; Fig. 2: a schematic view of the first steering shaft section with the first profiled disc arranged thereon; Fig. 3: a schematic view of the second steering shaft section with the second profiled disc arranged thereon; Fig. 4: a schematic side view of the two steering shaft sections with profile discs partially lifted from each other for the first steering device according to the invention according to Fig. 1; Fig. 5: a schematic sectional view of the two steering shaft sections and the two cooperating profile discs for the first steering device according to the invention; Fig. 6: a schematic diagram of a total torque versus a rotational speed of the steering column for the first steering device according to the invention; Fig. 7: a schematic diagram of an output torque versus an input torque; Fig. 8: a schematic sectional view of the second profile disc for a second steering device according to the invention with a torsional play; Fig. 9: a schematic, perspective view of profile discs lifted from one another for the second steering device according to the invention with a torsional play; Fig. 10: a schematic sectional view of a further steering device according to the invention with a torsion bar.

[0036] Fig. 1 shows a schematic first side view of a first steering device 1 according to the invention. The steering device 1 has a steering handle 5, which is connected to the first steering shaft section 2. The first steering shaft section 2 is connected to a first profiled disc 6, which has a first ramp profile 11. In this exemplary embodiment, the first profiled disc 6 and the first ramp profile 11 are formed from two independent bodies that are connected to one another in a torsionally rigid manner. However, it is also possible for both the first profiled disc 6 and the first ramp profile 11 to be formed as a one-piece component, in particular from the same material.

[0037] The steering device 1 further comprises a second steering shaft section 3, which lies on a common central longitudinal axis 4 with the first steering shaft section 2. In this exemplary embodiment, the steering handle 5 is also arranged on the central longitudinal axis 4. A feedback drive 9 is also arranged here, for example, on the central longitudinal axis 4, wherein the feedback drive 9 has an actuator and a reduction gear (not shown).

[0038] The second steering shaft section 3 is connected to the second profiled disc 7 via a toothing 10. The second profiled disc 7 can be axially displaced along the central longitudinal axis 4 via the toothing 10. The second profiled disc 7 and the second steering shaft section 3 are torsionally rigidly connected to one another via the toothing 10. A second ramp profile 12 is fastened to the second profiled disc 7 for interaction with the first profiled disc 6. In this exemplary embodiment, the second profiled disc 7 and the second ramp profile 12 are formed from two independent bodies that are torsionally rigidly connected to one another. Here, too, however, it is possible for the second profiled disc 7 and the first ramp profile 12 to be formed as a one-piece component, in particular from the same material.

[0039] A second brake part 15 is attached to the second profile disc 7. If the second ramp profile 12 moves along the central longitudinal axis 4, the second brake part 15 and the second profile disc 7 are also moved along the toothing 10.

[0040] The steering device 1 surrounds a housing (not shown in detail here) with a fixed brake part 16, which does not move relative to the first and second steering shaft sections 2, 3.

[0041] Furthermore, the steering device 1 has a pretensioning device 8, which pretensions the first profiled disc 6 and the second profiled disc 7 against each other. In this embodiment, the pretensioning device 8 is implemented by means of several tension springs.

[0042] During a first operating mode, in which the steering device does not generate any braking torque, the first profiled disc 6 and the second profiled disc 7 are pressed flat against one another. A resistance moment, which is noticeable to a vehicle driver at the steering handle 5, is transmitted in this mode only by the feedback drive 9 to the steering handle 5. If the resistance moment applied by the feedback drive 9 exceeds a limit torque, the first profiled disc 6 and the second profiled disc 7 slide against one another or away from one another. In this process, the second profiled disc 7 partially lifts off from the first profiled disc 6 and is displaced axially in the longitudinal direction of the central longitudinal axis 4 away from the first profiled disc 6. Together with the second profiled disc 7, the second brake part 15 is displaced in the axial direction of the central longitudinal axis 4, whereby the second brake part 15 is pressed against the stationary brake part 16.This creates an additional braking torque, which is superimposed on the resistance torque of the feedback drive 9.

[0043] If the resistance moment of the feedback drive 9 increases further, the braking torque between the second brake part 15 and the fixed brake part 16 also increases due to the separation forces of the profile discs.

[0044] If the resistance moment of the feedback drive 9 falls below the limit torque, the pretensioning device 8 pulls the first profiled disc 6 and the second profiled disc 7 towards each other, whereby the second brake part 15 and the fixed brake part 16 are released from each other and the braking torque of the steering device 1 is reduced.

[0045] The braking characteristics of the steering device 1 can be influenced by selecting the ramp profile, the stiffness of the preload device 8, and the clearance between the second brake part 15 and the stationary brake part 16. This allows a wide resistance torque range to be achieved, particularly in conjunction with the feedback drive 9.

[0046] Wear occurring between the second brake part 15 and the stationary brake part 16 causes the clearance to increase in a mode without braking torque. To adjust this clearance, an adjustment device (not shown) can be used to keep the clearance at a constant value. For example, the first profiled disc 6 and the second profiled disc 7 can be rotated relative to each other and fixed in this position.

[0047] Fig. 2 shows a first steering shaft section 2 with the first profiled disc 6. On one end face of the first profiled disc 6 are several ring segments 13, which are arranged along the circumferential direction. The ring segments 13 together form a ring shape. According to this exemplary embodiment, the first ramp profile 11 consists of four ring segments 13, which form a wave-shaped contour in the circumferential direction. Contour elevations of immediately adjacent ring segments 13 merge into one another. Contour valleys of immediately adjacent ring segments 13 also merge into one another. The contour elevations and contour valleys arise in the axial direction relative to the central longitudinal axis 4 of the steering shaft section 2. In addition to the four ring segments 13 shown, more or fewer ring segments 13 are also possible. However, at least one ramp profile is necessary to carry out the method.

[0048] Fig. 3 shows the second steering shaft section 3 with the second profiled disc 7 and the toothing 10. Complementary to the first profiled disc 6, the second profiled disc 7 also has a second ramp profile 12, which in this embodiment consists of four ring segments 13. Both profiled discs 6, 7 fit into each other with a phase offset of 90° and form according to Fig. 1 a surface contact. Furthermore, the second profiled disc 7 interacts with the toothing 10, which allows it to move axially along the central longitudinal axis 4. For this purpose, the second profiled disc 7 has a recess that is complementary to the toothing 10 of the second steering shaft section 3.

[0049] In Fig. Figure 4 shows a schematic side view of the two steering shaft sections 2, 3 with the profiled discs 6, 7 partially lifted from each other. The resistance moment generated by the feedback drive 9 in this case exceeds the limit torque of the steering device 1, with the first profiled disc 6 and the second profiled disc 7 sliding against each other, and the second profiled disc 7 moving axially along the central longitudinal axis 4 toward the stationary brake part 16. For better clarity, the stationary brake part 16 and the second brake part 15 are not shown.

[0050] The pretensioning device 8 pulls the first profile disc 6 and the second profile disc towards each other, whereby when the resistance moment of the feedback drive 9 is eliminated, the two profile discs are pressed together again.

[0051] Fig. 5 shows a schematic sectional view of the two steering shaft sections 2, 3 and the two cooperating profile discs 6, 7. As in Fig. 4 is also in Fig. Figure 5 shows the operating mode in which the first ramp profile 11 and the second ramp profile 12 slide against each other, generating a braking torque. In this case, the second brake part 15 is pressed against the stationary brake part 16, generating an additional braking torque.

[0052] Fig. 6 shows a schematic diagram of a total torque versus a rotational speed of the steering shaft for the steering device 1 according to the invention according to Fig. 1. The total torque 23 is plotted on the ordinate, and the rotational speed 24 is plotted on the abscissa. An assistance map 17 is shown above the x-axis, which applies to motor operation of the feedback drive 9. A resistance map 22 is shown below the abscissa, which applies to generator operation of the feedback drive 9. Furthermore, several exemplary operating points are shown in the maps 17, 22.

[0053] For example, at operating point 18, the feedback drive 9 is operated such that it supports a rotation of the first steering shaft section 2, while at operating point 21, for example, the feedback drive 9 is operated in a resistance mode that counteracts the rotation of the first steering shaft section 2.

[0054] Operating point 19 represents a state in which the steering handle 5 is moved only slowly, generating a high resistance torque. Operating point 19 corresponds, for example, to a situation in which a driver leans against the steering handle when getting in and / or out of the vehicle. The steering handle should be prevented from turning away, which is why the steering device 1 according to the invention generates an additional braking torque by means of the braking device 14 in this situation, which is superimposed on the resistance torque of the steering handle of the feedback drive 9.

[0055] Operating point 20 represents a state in which the steering handle is moved only slowly, providing a high resistance moment. This state corresponds to a situation in which a predetermined steering angle of the steering handle 5 is reached. The steering stop is generated by the resistance moment of the feedback drive 9 and the braking device 14 of the steering device 1.

[0056] The characteristics of the resistance map 22 can be influenced according to the selection of the clearance, the pretensioning device 8 and the pitch of the first profile disc 6 or the pitch of the second profile disc 7.

[0057] Fig. Figure 7 shows a schematic diagram of an output torque versus an input torque. The ordinate represents the output torque 30, and the abscissa represents the input torque 29. In the resistance mode of the feedback drive 9, a resistance torque is provided by the feedback drive 9 according to line 25. The actually resulting total torque, according to the second line 28, is lower than the resistance torque according to line 25 due to friction effects. As can be seen from the figure, the total torque of the first section line is linear. If a certain input torque 29 is present, the braking device 14 of the steering device 1 generates an additional braking torque, which is superimposed on the resistance torque of the feedback drive 9. The braking torque increases linearly according to line 26 and has a steeper gradient than the base line 28.Line 27 shows only the additional braking torque applied by the braking device 14 of the steering device 1. The curves in . Fig. The lines shown in Figure 7 for the input torque 29, the braking torque of the feedback drive 9, the total torque and the resistance torque according to line 25 may also have a different course than that shown and may have a non-linear function.

[0058] Fig. Figure 8 shows the second profiled disc 7 for a second steering device 1 according to the invention. Identical features bear the same reference numerals as before. To avoid repetition, reference is made to the preceding description.

[0059] In contrast to the previously shown second profiled discs 7 according to the first steering device 1 according to the invention, the profiled disc 7 shown here has a recess which allows for a torsional play 31 on the second steering shaft section 3. If the torsional play 31 is overcome, the profiled disc stop 33 comes into contact with the steering shaft stop 34, whereby a torque can be transmitted from the second profiled disc 7 to the second steering shaft section 3. A stop device 32 thus formed serves to ensure that a torque can only be transmitted via the second profiled disc 7 to the second steering shaft section 3 once a certain torsional play has been overcome. To connect the two steering shaft sections 2, 3, these are hollow in this embodiment and are designed with a torsion bar 35 arranged therein, not shown in detail here; see Fig. 10.

[0060] Fig. 9 shows a schematic, perspective view of profiled discs 6, 7, separated from one another, for the second steering device 1 according to the invention, with the torsional play. In this operating state, the second profiled disc 7 is already rotated relative to the second steering shaft section 3 such that the profiled disc stop 33 rests against the steering shaft stop 34. As a result, the first ramp profile 11 slides off the second ramp profile 12, causing the second profiled disc 7 to move axially along the central longitudinal axis 4. Analogous to the above description, the second brake part 15 is pressed against the stationary brake part 16, generating an additional braking torque.

[0061] The characteristics of the steering device 1 can be influenced or adjusted by the structural design of the torsional play, in particular a play in the circumferential direction.

[0062] Fig. Figure 10 shows a sectional view of another steering device according to the invention with profiled discs 6, 7 separated from each other. Identical features bear the same reference numerals as before. To avoid repetition, reference is made to the preceding description.

[0063] In this embodiment, the first steering shaft section 2 and the second steering shaft section 3 are each formed as a hollow shaft in which a torsion bar 35 is arranged. The torsion bar 35 has a first fastening section 36, which is fastened to the second steering shaft section 3. Furthermore, the torsion bar 35 has a second fastening section 37, which is fastened to the first steering shaft section 2.

[0064] In this embodiment, the profile disc 7 can be adjusted by a torsional play according to Fig.9. The torsion bar 35 introduces an additional elastic moment, which is perceptible to a driver via the steering handle 5. Only after the spring moment of the torsion bar 35 is overcome is the torsional play 31 overcome and the steering shaft stop 34 comes into contact with the profiled disc stop 33. Only then are the first profiled disc 6 and the second profiled disc activated, causing them to slide off one another. The torsional rigidity of the torsion bar 35 can be used to control the release torque of the braking device of the steering device 1.

[0065] If necessary, isolated features can also be extracted from the combinations of features disclosed here and used in combination with other features to define the subject matter of the claim, dissolving any structural and / or functional relationship between the features. The order and / or number of steps of the methods can be varied. The methods can be combined with one another, for example, into a single method. Reference symbol 1 steering device 2 First steering shaft section 3 Second steering shaft section 4 Central longitudinal axis 5 Steering handle 6 First profile disc 7 Second profile disc 8 Pre-tensioning device 9 Feedback drive 10 Gearing 11 First ramp profile 12 Second ramp profile 13 ring segment 14 Braking device 15 Second brake part 16 Fixed brake part 17 Assistance map 18 First operating point 19 Second operating point 20 Third operating point 21 Fourth operating point 22 Resistance map 23 Total torque 24 rotation speed 25 Line 25 26 Line 26 27 Line 27 28 Baseline 29 Input torque 30 Output torque 31 Backlash 32 Anchor device 33 Profile disc stop 34 Steering shaft stop 35 Torsion bar 36 First fortification section 37 Second fortification section 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] DE 10 2023 202 440 A1

[0002]

Claims

[1] Steering device (1) for a motor vehicle, with a fixed first brake part (16) and a steering shaft, wherein the steering shaft is mounted rotatably about its central longitudinal axis (4) and the steering shaft has a first steering shaft section (2) and the steering shaft further has a second steering shaft section (3) with a second brake part (15) arranged thereon, wherein the second brake part (15) is pressed against the fixed brake part (16) when a braking force is present, characterized by that a first profiled disc (6) is arranged on the first steering shaft section (2) and a second profiled disc (7) is arranged on the second steering shaft section (3), the braking force being generated due to a differential speed between the two interacting profiled discs (6, 7). [2] Steering device (1) according to claim 1, characterized byin that the first profile disc (6) has a first ramp profile (11) which interacts with a complementarily designed second ramp profile (12) of the second profile disc (7), preferably in a rotation mode the two ramp profiles (11, 12) lie against one another with a maximum contact surface and in a braking mode the two profile discs (6, 7) are partially lifted away from one another in the axial direction of the central longitudinal axis (4), whereby the braking force is generated. [3] Steering device (1) according to one of the preceding claims, characterized by that the first profiled disc (6) and / or the second profiled disc (7) is connected in a rotationally fixed manner to the associated first steering shaft section (2) or second steering shaft section (3), wherein the first profiled disc (6) or the second profiled disc (7) is arranged axially along the central longitudinal axis (4) and displaceably relative to the associated steering shaft section (2, 3). [4] Steering device (1) according to one of the preceding claims, characterized by in that the first profiled disc (6) and second profiled disc (7) are prestressed towards one another by means of a prestressing device (8) against lifting off in the axial direction to the central longitudinal axis (4), wherein the braking force is only applied after a prestressing force provided by the prestressing device (8) has been overcome, in particular the prestressing force of the prestressing device (8) counteracts a transition from a rotation mode to a braking mode, preferably the prestressing device (8) has at least one tension spring element, wherein the tension spring element is connected with a first end to the first profiled disc (6) and with a second end facing away from the first end to the second profiled disc (7). [5] Steering device (1) according to one of the preceding claims, characterized bythat the second steering shaft section (3) is connected to a feedback drive (9) for generating a resistance moment, in particular the feedback drive (9) is arranged at an end of the second steering shaft section (3) facing away from the second profiled disc (7), preferably a steering handle (5) is arranged at an end of the first steering shaft section (2) facing away from the first profiled disc (6). [6] Steering device (1) according to claim 5, characterized by that a braking torque applied to a steering handle (5) between the first brake part (16) and the second brake part (15) is proportional to the resistance torque, in particular the resistance torque and the braking torque are superimposed to form a total braking torque. [7] Steering device (1) according to one of the preceding claims, characterized bythat at least one rolling body is arranged between the two profiled discs (6, 7), preferably the rolling body is rotationally symmetrical to reduce friction between the two profiled discs (6, 7). [8] Steering device (1) according to one of claims 2 to 7, characterized by that the two ramp profiles (11, 12) each have a plurality of ring segments (13), wherein each ring segment (13) has a ramp surface and the ramp surfaces rise from a first end of a ring segment (13) to a second end of the same ring segment (13) in the axial direction to the central longitudinal axis (4), and in each case first ends of immediately adjacent ring segments (13) and in each case second ends of immediately adjacent ring segments (13) lie against one another and / or merge into one another. [9] Steering device (1) according to one of the preceding claims, characterized bythat the steering device (1) has a torsion bar (35), wherein a first part of the torsion bar (35) is fastened to the first steering shaft section (2) and a second part of the torsion bar (35) is fastened to the second steering shaft section (3), in particular a central longitudinal axis (4) of the torsion bar (35) coincides with the central longitudinal axis (4) of the steering shaft. [10] Steering device (1) according to one of the preceding claims, characterized byin that the first steering shaft section (2) or the second steering shaft section (3) is rotatable about the central longitudinal axis (4) in relation to the associated first profiled disc (6) or second profiled disc (7) due to a predetermined torsional play (31), wherein after overcoming the torsional play (31) the first profiled disc (6) or the second profiled disc (7) strikes a stop device (32) of the associated first steering shaft section (2) or the second steering shaft section (3), in particular the two profiled discs (6, 7) are partially lifted away from one another after overcoming the torsional play (31) and further rotation of the steering shaft in the same direction of rotation, whereby the braking force is generated. [11] Steering device (1) according to one of the preceding claims, characterized bythat the steering device (1) has an adjusting mechanism with a further brake part, wherein the further brake part is arranged rotationally fixed with respect to the central longitudinal axis (4) of the steering shaft and the adjusting mechanism produces a braking effect on the steering shaft in a first mode, in particular in the first mode the further brake part is pressed against the second brake part (15), preferably in a second mode of the adjusting mechanism the further brake part is moved into a position detached from the second brake part (15). [12] Steering device (1) according to claim 11, characterized by that the actuating mechanism is an electromechanical actuator and the first mode is triggered in a de-energized state of the actuating mechanism. [13] Steer-by-wire steering with a steering device (1) according to one of the preceding claims.

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