Steering device for a motor vehicle, steering by wire system and motor vehicle

Abstract

A steering device (100a, 100b, 200a, 200b, 310, 410) for a motor vehicle (400), in particular for use in a steer-by-wire system (300, 402), comprises a steering handle (110) that is rotatable about an axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410), and a handle (110) that is rotatable about an axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410). And a recovery torque generating device (120a, 120b, 220a, 220b) engaged with the steering handle (110) and configured to generate a torque that at least partially counteracts rotation of the steering handle (110). The recovery torque generating device (120a, 120b, 220a, 220b) includes: a motor (130) having a hollow core (136) coaxial with an axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410); and a gear (140a, 140b, 240a, 240b) engaged with the motor (130) and configured to transmit torque generated by the motor (130) to the steering handle (110). The gear (140a, 140b, 240a, 240b) has a hollow central region (142, 242) coaxial with the axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410) and a gear ratio in the range of 20: 1 to 100: 1.

Description

[0001] The present application relates to a steering device for a motor vehicle. The present application also relates to a wire control steering system and a motor vehicle. Background Art

[0002] In conventional steering systems, for example in motor vehicles, the desired steering angle input by the driver is mechanically transmitted to the steerable wheel suspension via a steering gear. In contrast, in the case of a steer-by-wire system, the driver's input via the steering handle is detected by electrical means and transmitted to an actuator for steering the wheels. Detecting the driver's steering input is usually performed with the aid of one or more sensors, and the sensor signals are processed with the aid of a control unit, which then generates corresponding control signals for operating the steering actuator.

[0003] In a steer-by-wire system, the wheels of a motor vehicle are mechanically decoupled from the steering handle. As a result, the forces acting on the wheels during a steering maneuver are not transmitted to the steering handle. In order to provide the driver with a driving feel similar to that of a conventional steering system, it is known to include a restoring torque generating device in the steering system. The restoring torque generating device generally comprises an electric motor that can be controlled to exert a torque on the steering handle, the torque being adaptable in magnitude and direction to the current driving and / or steering conditions.

[0004] Providing a restoring torque generating device in a steering device goes against the general desire for a compact arrangement of the steering device in a vehicle. This problem is exacerbated by the need for a gear that typically needs to be arranged between the motor of the restoring torque generating device and the steering handle.

[0005] Furthermore, the inclusion of a restoring torque generating device in a steering device often prevents proper integration of electrical, optical or other kind of supply lines for interface functions, such as electrical and / or optical wiring, arranged at the steering handle.

[0006] Furthermore, when the driver turns the steering handle, the restoring torque applied to the steering handle by the restoring torque generating device is usually resisted and overcome by him or her. In many cases, this results in a high load condition of the electric motor, with the motor not rotating or rotating less and / or differently than that corresponding to the applied current. This usually results in undesirable heating of the motor.

[0007] However, even at low currents, the motors heat up. For example, when driving on a straight road, the vehicle driver tends to make slight steering movements, including subconscious steering movements, or tends to steer slowly to either side alternately. In this case, the restoring torque generating device can be activated by a slight displacement of the steering handle, while substantially no steering movement occurs. As a result, the operating current of the electric motor of the restoring torque generating device remains applied to the motor at the same electrical phase for a longer period of time. This can cause overheating of the motor components.

[0008] Therefore, there is a need for a technique that avoids or at least mitigates at least one of the aforementioned disadvantages. Summary of the invention

[0009] Therefore, a steering device according to claim 1, a steer-by-wire system according to claim 17 and a vehicle according to claim 18 are provided.

[0010] According to a first aspect, a steering device for a motor vehicle is provided, in particular for use in a steer-by-wire system. The steering device comprises: a steering handle rotatable about an axis of the steering device; and a restoring torque generating device engaged with the steering handle and configured to generate a torque that at least partially counteracts the rotation of the steering handle. The restoring torque generating device comprises: a motor having a hollow core coaxial with the axis of the steering device; and a gear engaged with the motor and configured to transmit the torque generated by the motor to the steering handle. The gear has a hollow central area coaxial with the axis of the steering device and a gear ratio in the range of 20:1 to 100:1.

[0011] Thus, a compact realization of a restoring torque generating device in a steering device is facilitated. Furthermore, the integration of at least one electrical, optical and / or other type of supply line for one or more interface functions arranged at the steering handle and / or the steering system is improved. Furthermore, heating of the motor of the restoring torque generating device can be avoided or reduced.

[0012] The gear ratio may be in the range of 20:1 to 75:1, preferably in the range of 20:1 to 50:1, preferably in the range of 22:1 to 38:1, preferably in the range of 25:1 to 35:1, more preferably in the range of 28:1 to 32:1.

[0013] The gear ratio is preferably selected so that a small displacement of the steering handle, in particular a displacement leading to activation of the restoring torque generating device, corresponds to a switch between the different electrical phases of the motor. Furthermore, the gear ratio is preferably selected so that a typical steering maneuver does not correspond to an excessively high number of revolutions of the motor, at which undesirable motor noises could occur.

[0014] The steering device may also include an at least partially hollow steering column extending through the hollow core of the motor and the hollow center region of the gear.

[0015] The motor may include a stator and a rotor. The stator may be an inner stator and the rotor may be an outer rotor.

[0016] In some configurations, the motor may also be configured to rotate the steering handle at least partially depending on the current driving situation. More precisely, in particular in semi-automatic and / or fully automatic vehicles, the motor may be configured to rotate the steering handle at least partially depending on the steering of the vehicle. More precisely, the motor may rotate the steering handle during a transition operation from an automatic or semi-automatic driving state to a manual driving state or vice versa, i.e. during a transition situation where the driver hands over the steering to the system or vice versa.

[0017] The gear may be arranged to at least partially overlap the motor in a radial direction relative to the axis of the steering device. Additionally or alternatively, the gear may be arranged to at least partially overlap the motor in an axial direction along the axis of the steering device.

[0018] The gear may comprise a strain wave gear or a harmonic gear. Additionally or alternatively, the gear may comprise a planetary gear.

[0019] The gear may include an inner gear member configured to be driven by a motor, at least one intermediate gear member and an outer gear member. The at least one intermediate gear member may mesh with an outer surface of the inner gear member and an inner surface of the outer gear member.

[0020] The rotor may be formed integrally with the inner gear member of the gear. Thus, it is possible to reduce or avoid the extension of the gear beyond the motor in the axial direction toward the steering handle.

[0021] The outer gear member may be arranged to be rotationally fixed relative to the steering handle. In this case, the intermediate gear member may be arranged to be rotationally and axially fixed relative to the at least partially hollow steering column and / or the stator.

[0022] As an alternative, the intermediate gear member may be arranged to be rotationally fixed relative to the steering handle.In this case, the outer gear member may be arranged to be rotationally and axially fixed relative to the at least partially hollow steering column and / or stator.

[0023] The intermediate gear member and / or the internal gear member may be arranged to at least partially surround the motor in a radial direction. Additionally or alternatively, the intermediate gear member and / or the internal gear member may be arranged to at least partially surround the motor in an axial direction.

[0024] In an embodiment of the steering device in which the gear comprises a strain wave gear, the intermediate gear member may comprise a flexible spline of the strain wave gear. In addition, the inner gear member may comprise a wave generator of the strain wave gear rotatably arranged within the flexible spline, and the outer gear member may comprise a circular spline of the strain wave gear.

[0025] In an embodiment of a steering device in which the gears include planetary gears, the inner gear member may include a sun gear of the planetary gears. In addition, the intermediate gear member may include a device of one or more planetary gears rotatably attached to a carrier, and the outer gear member may include a ring gear of the planetary gears.

[0026] The restoring torque generating device may also include at least one cooling device configured to provide cooling to the motor when the motor is in motion.

[0027] The steering device may also include at least one electrical and / or optical interface function arranged at the steering handle and / or in the steering system. The electrical wiring, optical wiring and / or optical path of the at least one electrical and / or optical interface function may extend at least partially within the hollow core of the motor and / or within the hollow center area of ​​the gear.

[0028] The at least one electrical and / or optical interface function may comprise at least one of a heating element, a display, a light element, an airbag or a control element of the steering handle.

[0029] The steering device may further comprise at least one sensor device. The at least one sensor device may be configured to detect a steering input provided by a user via a steering handle and to generate a sensor signal indicative of the detected steering input.

[0030] According to another aspect, a steer-by-wire system is provided, in particular for use in a motor vehicle. The steer-by-wire system comprises a steering device as presently provided.

[0031] According to another aspect, a motor vehicle is provided. The motor vehicle comprises a steer-by-wire system as presently provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Further details, advantages and objects of the present invention become apparent through the accompanying drawings and detailed description. In the accompanying drawings, there are shown:

[0033] Figures 1A to 2B A steering device for a motor vehicle according to various examples;

[0034] Figure 3 A steer-by-wire system according to an example, in particular for use in a motor vehicle, and

[0035] Figure 4A motor vehicle including a steer-by-wire system according to an example. DETAILED DESCRIPTION

[0036] Figure 1A A steering device 100a is schematically and exemplarily shown, in particular for use in a motor vehicle. The steering device 100a comprises a steering handle 110 rotatably mounted about an axis A. By rotating the steering handle 110 about the axis A, a user provides a steering input to the steering device 100a. In the example shown, the steering handle 110 is supported by a steering column 115 of the steering device 100a and is rotatably attached to the steering column 115 via a steering handle bearing 112. The steering column 115 can be configured to be rigidly mounted relative to a chassis of a motor vehicle in which the steering device 100a is used, for example as part of a steer-by-wire system.

[0037] The steering device 100a further includes a restoring torque generating device 120a. The restoring torque generating device 120a is arranged to apply a restoring torque on the steering handle 110 when the user provides a steering input through the steering handle 110, and the restoring torque at least partially counteracts the rotation of the steering handle 110. The restoring torque generating device 120a includes a motor 130 and a gear 140a. The stator 132 of the motor 130 is rotationally fixed relative to the steering column 115, and the rotor 134 of the motor 130 is rotationally fixed relative to the steering handle 110 through the gear 140a. Therefore, the torque generated by the motor 130 is transmitted to the steering handle 110 via the gear 140a, resulting in the generation of torque between the steering handle 110 and the steering column 115.

[0038] The motor 130 has a hollow core 136. In addition, the gear 140a has a hollow central area 142. Therefore, the restoring torque generating device 120a can provide a hollow conduit H extending through the hollow core 136 of the motor 130 and the hollow central area 142 of the gear 140a. In the example shown, the hollow conduit H extends through the steering column 115 coaxially with the axis A of the steering device 100a.

[0039] The hollow conduit H facilitates the arrangement of one or more electrical and / or optical interface functional parts 190 arranged at the steering handle 110, because the electrical or optical wiring and / or optical path 192 of the electrical and / or optical interface functional parts 190 and any other type of supply line can be accommodated in the hollow conduit H.

[0040] The hollow duct H thus facilitates a compact and robust arrangement of electrical, optical or any other kind of provision of interface functions arranged at the steering handle 110 .

[0041] At least one electrical and / or optical interface function 190 includes, for example: a heater for the steering handle 110; a display for outputting graphical information to a user; lighting (such as decorative lighting, an illuminated logo, or lighting of a control function arranged at the steering handle 110); an air bag housed in some examples of the steering handle 110; or any kind of control, such as one or more control buttons, a control wheel, a touch-sensitive control element, etc. In addition to electrical or optical wiring that may be housed in the hollow conduit H, the hollow conduit H may also be part of an optical path for light to propagate inside the hollow conduit H, for example, as part of an optical projection toward the steering handle 110.

[0042] The steering device 100a also includes a sensor device 180a. The sensor device 180a is configured to detect a steering input provided by a user via the steering handle 110, and to generate a sensor signal indicating the detected steering input. The sensor device 180a is suitable for detecting one or more physical characteristics indicating the steering input provided via the steering handle 110 (such as the steering angle or movement of the steering handle 110 relative to the steering column 115 or the chassis of the motor vehicle on which the steering device 100a is installed, etc.), and is suitable for generating a sensor signal corresponding to the one or more physical characteristics detected. The sensor signal is output by the sensor device 180a to a control unit (for example, a control unit of a steer-by-wire system of a motor vehicle). Based on the sensor signal, the control unit generates a control signal in some examples to output to the motor 130, thereby at least partially offsetting the detected steering input. For example, a control signal for the motor 130 is generated so that the voltage applied to the motor 130 increases according to the increased steering angle input via the steering handle 110.

[0043] In some examples, the sensor signal is further configured to be used by the control unit for determining corresponding control signals to be output to one or more steering actuators of the steering system.

[0044] The gear 140a is a strain wave gear. It comprises an internal gear member in the form of a wave generator 150. The wave generator 150 is rotatably arranged relative to the steering column 115, to which the wave generator 150 is attached via a first wave generator bearing 152 and a second wave generator bearing 154. The wave generator 150 is driven by the motor 130. To this end, the wave generator 150 is connected to the rotor 134 of the motor 130. On the outside of the wave generator 150, the wave generator 150 meshes with the inner surface of the intermediate member of the gear 140a in the form of a flexible spline 160a via a flexible spline bearing 168.

[0045] The flexible spline 160 is flexible in cross section. Furthermore, in the example shown, the flexible spline 160a is rotationally fixed relative to the steering column 115. The wave generator 150 has a cam-shaped periphery, generally similar to an ellipse. Therefore, rotating the wave generator 150 by operating the motor 130 will cause an elliptical deformation of the cross section of the flexible spline 160a, which propagates along the periphery of the flexible spline 160a in a rotational manner.

[0046] The gear 140a also includes an external gear member in the form of a circular spline 170a. In the example shown, the circular spline 170a is rotationally fixed relative to the steering handle 110. In addition, a toothed outer profile 162a located on the outer side of the flexible spline 160a meshes with a toothed inner profile 172a of the circular spline 170a. The size of the cam shape of the wave generator is configured so that the toothed outer profile 162a and the toothed inner profile 172a mesh near the vertex area of ​​each cam, while the toothed outer profile 162a and the toothed inner profile 172a are disengaged in an area away from the vertex area of ​​each cam, which is affected by the deformation of the cross section of the flexible spline 160a. When the wave generator 150 moves, the difference between the number of teeth contained in the toothed outer profile 162a and the toothed inner profile 172a causes relative rotation between the flexible spline 160a and the circular spline 170a. Because the flexible spline 160 a is rotationally fixed in the example shown, relative rotation between the flexible spline 160 a and the circular spline 170 a causes the steering wheel 110 to rotate relative to the steering column 115 .

[0047] Gear 140a is configured to have a gear ratio in the range of 20: 1 to 100: 1. In some examples, the gear ratio of gear 140a is in the range of 22: 1 to 38: 1, preferably, in the range of 25: 1 to 35: 1, and more preferably, in the range of 28: 1 to 32: 1.

[0048] It has been found that a gear ratio within the aforementioned range is advantageous for avoiding overheating of the motor 130 due to continuous application of current to the same electrical phase of the motor 130, for example, at small input angles (which typically occur when driving on a straight road for a long time). The gear ratio within the aforementioned range ensures that electrical phase switching occurs even at only typically small input angles. That is, the gear ratio is large enough so that even a small change in the input angle at the steering handle 110 typically corresponds to an angle of more than at least one phase switch of the rotor 134 of the motor 130.

[0049] In addition, it has been found that the gear ratio within the above range is advantageous for avoiding undesirable noise of the motor 130 due to the high number of revolutions of the motor 130, for example, in normal steering operation. If the input angle at the steering handle 110 corresponds to the angle of the rotor 134 of the motor 130 according to the gear ratio in normal steering operation exceeds an excessive number of revolutions, noise is generally generated. That is, it has been found that a small gear ratio within the above range is advantageous for avoiding an excessively high number of revolutions of the motor 130 in normal driving situations.

[0050] The gear 140a is also arranged so that it partially overlaps with the motor 130 in the radial direction R and surrounds the motor 130. In this way, a compact arrangement of the steering device 100 is facilitated. In the example shown, the gear 140a also overlaps with the motor 130 in the axial direction (i.e., in a direction parallel to the axis A) and surrounds the motor 130. In particular, the motor 130 is surrounded by the wave generator 150 and its bearings 152, 154.

[0051] In other examples, the motor 130 is not surrounded by the gear 140a in the axial direction. In some examples, the wave generator 150 is formed integrally with the rotor 134 of the motor 130. In this case, the additional wave generator bearings 152, 154 can be omitted. In addition, in some examples, the gear 140a does not extend beyond the motor 130 in the direction toward the steering handle 110. In this way, the compact arrangement of the restoring torque generating device 120a is further facilitated.

[0052] The steering device 100a also includes at least one cooling device 122a. The cooling device 122a provides cooling for the motor 130, especially when the motor 130 is moving. A simple implementation of the cooling device 122a includes a vent or ventilation grid that is arranged in the flexible spline 160a and allows warm air to be exhausted from the inside of the flexible spline 160a and replaced by cool air from the outside. In other examples, the cooling device 122a also includes a fan that is driven by the motor 130 and increases the air exchange between the inside and outside of the flexible spline 160a and / or between the inside and outside of the wave generator 150. Other examples of the cooling device 122a include additional devices or other devices for transferring heat from the motor 130 to the outside of the steering device 100a.

[0053] exist Figure 1AIn the example shown in , the circular spline 170a is rotationally fixed relative to the steering handle 110, and the flexible spline 160a is rotationally fixed relative to the steering column 115 and the stator 132. In other examples, as shown in FIG. 1b, the steering device 100b includes a restoring torque generating device 120b having a gear 140b, wherein the flexible spline 160b is rotationally fixed relative to the steering handle 110, and the circular spline 170b is rotationally fixed relative to the steering column 115 and the stator 132. The direction of the resultant movement of the steering handle 110 relative to the direction of the motor 130 in the steering device 100b is opposite to the direction of the resultant movement of the steering handle 110 relative to the direction of the motor 130 in the steering device 100a. Therefore, the operation of the motor 130 is adjusted accordingly. Furthermore, when sizing either of the gears 140a, 140b, it is to be taken into account that the effective gear ratio of the strain wave gear varies depending on whether the gear output is produced by a circular spline or a flexible spline, in which case the nominal gear ratio applies, i.e., n:1, while in the former case the effective gear ratio is increased by 1 relative to the nominal gear ratio, i.e., (n+1):1.

[0054] The steering device 100b further comprises a toothed outer profile 162b of the flexible spline 160b, a toothed inner profile 172b of the circular spline 170b, a cooling device 122b and a sensor device 180b. According to the aforementioned differences between the gears 140a and 140b, these features correspond functionally and structurally to the corresponding elements 162a, 172a, 122a, 180a of the steering device 100a, as will be seen by Figure 1A and Figure 1B It is worth noting that in Figure 1B In the example shown in , the sensor device 180 b is arranged to detect relative movement between the flexible spline 160 b and the steering column 115 .

[0055] exist Figure 1A and Figure 1B In the example shown in FIG. 1 , each of the steering devices 100a, 100b includes a steering column 115 extending through the hollow core 136 and the hollow center region 142 of the gears 140a, 140b. In other examples, the steering devices 100a, 100b do not include the steering column 115. Instead, in some examples, the stator 132 is attached to the base plate, and the gears 140a, 140b and the steering handle 110 are flanged to each other and to the rotor 134 without the need for additional support of the steering column.

[0056] Figure 2A Schematically and exemplarily, a steering device 200a according to another example is shown, in particular for use in a motor vehicle. Unless otherwise specified or implicitly clear from the following text, Figure 1AThe above description of the steering device 100a shown in FIG. 1 applies accordingly to Figure 2A The steering device 200a shown in FIG. Figure 1A Reference numerals which are the same as those in the reference numerals in the accompanying drawings denote the same or similar features serving the same purpose.

[0057] The steering device 200a comprises a restoring torque generating device 220a including an electric motor 130 and a gear 240a. The gear 240a comprises a planetary gear. In the arrangement shown, the sun gear 250 forms an inner gear member of the gear 240a driven by the motor 130. An arrangement 260a of one or more planetary gears rotatably attached to a carrier and each having a toothed profile 262a constitutes an intermediate gear member. A ring gear 270a having a toothed inner profile 272a constitutes an outer gear member of the planetary gear 240a.

[0058] right Figure 1A The description of the strain wave gear 140a in FIG. 1 applies accordingly to Figure 2A In particular, in the steering device 200a, the ring gear 270a is rotationally fixed relative to the steering handle 110, and the device 260a of one or more planetary gears rotatably attached to the bracket is rotationally fixed relative to the steering column 115 and the stator 132. In addition, the steering device 200a includes a cooling device 222a. The cooling device 222a basically corresponds to the cooling device 122a of the steering device 100a and is structurally applicable to the gear 240a.

[0059] In other examples, as shown in Figure 2b, the steering device 200b includes a restoring torque generating device 220b having a gear 240b, wherein a device 260b of one or more planetary gears rotatably attached to a bracket is rotationally fixed relative to the steering handle 110, and a ring gear 270b is rotationally fixed relative to the steering column 115 and the stator 132.

[0060] The steering device 200b also includes a tooth profile 162b at each planetary gear, a tooth inner profile 272b of the ring gear 270b, a cooling device 222b and a sensor device 180b. According to the aforementioned differences between the gears 240a and 240b, these features correspond functionally and structurally to the corresponding elements 262a, 272a, 222a, 180a of the steering device 200a, as will be explained by Figure 2A and Figure 2B Understandable. It is worth noting that Figure 2B In the example shown in , the sensor arrangement 180b is arranged to detect relative movement between the steering column 115 and an arrangement 260b of one or more planetary gears rotatably attached to a carrier.

[0061] In some examples of the steering devices 200a, 200b, the sun gear 250 is disposed separately from the rotor 134 of the motor 130. In other examples of the steering devices 200a, 200b, the sun gear 250 is formed integrally with the rotor 134 of the motor 130.

[0062] Figure 3 Schematically and exemplarily, a steer-by-wire system 300 is shown, in particular for use in a motor vehicle. The steer-by-wire system 300 comprises a steering device 310. The steering device 310 is a device that is configured to be coupled to a motor vehicle. Figures 1A to 2B The steering devices 100a, 100b, 200a, 200b shown in Figure 1 describe the steering devices.

[0063] The steer-by-wire system 300 further comprises a control unit 320. The control unit 320 is operably connected to the steering device 310. The control unit 320 comprises a processing unit and is configured to receive a sensor signal from a sensor device of the steering device 310. The sensor signal indicates a steering input provided by a user at the steering device 310. The control unit 320 is further configured to generate a control signal for operating a motor of a restoring torque generating device of the steering device 310 by means of the processing unit and at least partly based on the received sensor signal, and is configured to output the generated control signal to the motor of the steering device 310. In some examples, the control unit 320 is further configured to generate a control signal for the restoring torque generating device based on additional information such as a current speed of the motor vehicle, a current inclination of the motor vehicle, a current terrain, wheel slip, etc.

[0064] Furthermore, the control unit 320 is configured to generate control signals for operating one or more steering actuators 330 of the motor vehicle by means of the processing unit and at least partly based on the received sensor signals. The control unit 320 is also configured to output the generated control signals to the one or more steering actuators 330.

[0065] Figure 4 A motor vehicle 400 is shown schematically and exemplarily. The motor vehicle 400 includes a motor vehicle 400 having a motor vehicle 400 coupled to a motor vehicle 400. Figure 3 The steer-by-wire system 402 is described with reference to the steer-by-wire system 300 shown in FIG. In particular, the steer-by-wire system 402 includes a steering device 410, a control unit 420, and one or more steering actuators 430. The steering device 410 is a control unit 420. Figures 1A to 2B The control unit 420 is such as in combination with the steering device 100a, 100b, 200a, 200b described in the steering device shown in FIG. Figure 3 The control unit 320 of the steer-by-wire system 300 shown in FIG.

Claims

1. A steering device (100a; 100b; 200a; 200b; 310; 410) for a motor vehicle (400), in particular for use in a steer-by-wire system (300; 402), the steering device (100a; 100b; 200a; 200b; 310; 410) including: a steering handle (110) rotatable about an axis (A) of the steering device (100a; 100b; 200a; 200b; 310; 410); and A restoring torque generating device (120a; 120b; 220a; 220b) is engaged with the steering handle (110) and is configured to generate a torque that at least partially offsets the rotation of the steering handle (110), the restoring torque generating device (120a; 120b; 220a; 220b) comprising: a motor (130) having a hollow core (136) coaxial with the axis (A) of the steering device (100a; 100b; 200a; 200b; 310; 410); and a gear (140a; 140b; 240a; 240b) engaged with the motor (130) and configured to transmit the torque generated by the motor (130) to the steering handle (110), It is characterized in that The gear (140a; 140b; 240a; 240b) has a hollow central region (142; 242) coaxial with the axis (A) of the steering device (100a; 100b; 200a; 200b; 310; 410) and a gear ratio in the range of 20:1 to 100:

1.

2. The steering device according to claim 1, wherein: The gear ratio is in the range of 22:1 to 38:1, preferably in the range of 25:1 to 35:1, more preferably in the range of 28:1 to 32:

1.

3. A steering device according to claim 1 or claim 2, further comprising an at least partially hollow steering column (115) extending through the hollow core (136) of the motor (130) and the hollow central region (142; 242) of the gear (140a; 140b; 240a; 240b).

4. A steering device according to any one of the preceding claims, wherein: The motor (130) comprises a stator (132) and a rotor (134), wherein preferably, the stator (132) is an inner stator and the rotor (134) is an outer rotor.

5. A steering device according to any one of the preceding claims, wherein: The gear (140a; 140b; 240a; 240b) is arranged to at least partially overlap with the motor (130) in a radial direction (R) relative to the axis (A) of the steering device (100a; 100b; 200a; 200b; 310; 410) and / or to at least partially overlap with the motor (130) in an axial direction along the axis (A) of the steering device (100a; 100b; 200a; 200b; 310; 410).

6. A steering device according to any one of the preceding claims, wherein: The gear (140a; 140b; 240a; 240b) includes a strain wave gear (140a; 140b) and / or a planetary gear (240a; 240b).

7. The steering device according to claim 5 or claim 6, wherein: The gear (140a; 140b; 240a; 240b) comprises an internal gear member (150; 250), at least one intermediate gear member (160a; 160b; 260a; 260b) and an external gear member (170a; 170b; 270a; 270b), wherein the internal gear member (150; 250) is configured to be driven by the motor (130), and the at least one intermediate gear member (160a; 160b; 260a; 260b) is meshed with an outer surface of the internal gear member (150; 250) and meshed with the external gear member (170a; 170b; 270a; 270b). 270b) inner surface meshing.

8. Steering device according to claim 7 in combination with at least one of claim 3 and claim 4, wherein: The outer gear member (170a; 270a) is arranged to be rotationally fixed relative to the steering handle (110), and the intermediate gear member (160a; 260a) is arranged to be rotationally and axially fixed relative to the at least partially hollow steering column (115) and / or the stator (132), respectively.

9. The steering device according to claim 7 in combination with at least one of claim 3 and claim 4, wherein: The intermediate member (160b; 260b) is arranged to be rotationally fixed relative to the steering handle (110), and the outer gear member (170b; 270b) is arranged to be rotationally and axially fixed relative to the at least partially hollow steering column (115) and / or the stator (132), respectively.

10. The steering device according to any one of claims 7 to 9 in combination with claim 5, wherein: The intermediate gear member (160a; 160b) and / or the internal gear member (150) are arranged to at least partially surround the motor (130) in a radial direction (R) and / or an axial direction.

11. The steering device according to any one of claims 7 to 10 in combination with claim 6, wherein: The gear (140a; 140b; 240a; 240b) comprises a strain wave gear (140a; 140b), and wherein the intermediate gear member (160a; 160b; 260a; 260b) comprises a flexible spline (160a; 160b), the internal gear member (150; 250) comprises a wave generator (150) rotatably arranged within the flexible spline (160a; 160b), and the external gear member (170a; 170b; 270a; 270b) comprises a circular spline (170a; 170b) of the strain wave gear (140a; 140b).

12. The steering device according to any one of claims 7 to 10 in combination with claim 6, wherein: The gears (140a; 140b; 240a; 240b) include planetary gears (240a; 240b), and wherein the internal gear member (150; 250) includes a sun gear (250), the intermediate gear member (160a; 160b; 260a; 260b) includes a device (260a; 260b) of one or more planetary gears rotatably attached to a carrier, and the external gear member (170a; 170b; 270a; 270b) includes a ring gear (270a; 270b) of the planetary gears (240a; 240b).

13. A steering device according to any one of the preceding claims, wherein: The restoring torque generating device (120a; 120b; 220a; 220b) further comprises at least one cooling device (122a; 122b; 222a; 222b) configured to provide cooling to the motor (130) when the motor (130) moves, and / or Also included is at least one sensor device (180a; 180b) configured to detect a steering input provided by a user via the steering handle (110), and configured to generate a sensor signal indicative of the detected steering input.

14. The steering device according to any of the preceding claims, further comprising at least one electrical and / or optical interface function (190) arranged at the steering handle (110), wherein: The electrical wiring, optical wiring and / or optical path (192) of the at least one electrical and / or optical interface functional part (190) extend at least partially within the hollow core (136) of the motor (130) and / or within the hollow center area (142; 242) of the gear (140a; 140b; 240a; 240b), wherein, optionally, the at least one electrical and / or optical interface functional part (190) includes at least one of a heating element, a display, a lighting element, an airbag or a control element of the steering handle (110).

15. A steer-by-wire system (300), in particular for use in a motor vehicle (400), comprising a steering device (310) according to any one of the preceding claims.

16. A motor vehicle (400) comprising a steer-by-wire system according to claim 15.

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