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

Abstract

A steering device (100a, 100b, 200a, 200b, 310, 410) for use in a motor vehicle (400), particularly for use in a steer-by-wire steering system (300, 402), comprises a steering wheel (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) coupled to the steering wheel (110) and configured to generate a torque that at least partially cancels the rotation of the steering wheel (110). The restoring torque generating device (120a, 120b, 220a, 220b) comprises 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) coupled to the motor (130) and configured to transmit the torque generated by the motor (130) to the steering wheel (110). The gear (140a, 140b, 240a, 240b) has a hollow central region (142, 242) coaxial with an 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

Technical Field

[0001] The present application relates to a steering device used for a motor vehicle. The present application further relates to a steer-by-wire steering system and a motor vehicle.

Background Art

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

[0003] In a steer-by-wire steering system, the wheels of a motor vehicle are mechanically disconnected from the steering wheel. As a result, the forces acting on the wheels during steering operation are not transmitted to the steering wheel. In order to provide the driver with a driving feeling 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 usually comprises an electric motor controllable to actuate a torque on the steering wheel, and this torque can be adapted in intensity and direction to the current driving and / or steering state.

[0004] Providing a restoring torque generating device in a steering device runs counter to the general desire for a compact arrangement of the steering device in a vehicle. This problem is usually exacerbated by the need for gears that need to be arranged between the motor of the restoring torque generating device and the steering wheel.

[0005] In addition, including a restoring torque generating device in the steering apparatus often hinders proper integration of electrical, optical, or other types of supply lines (such as electrical wiring and / or optical wiring) used for an interface functional member disposed on the steering handle.

[0006] Furthermore, the restoring torque applied to the steering handle by the restoring torque generating device is generally counteracted and overcome when the driver turns the steering handle. In many cases, this leads to a high-load state of the electric motor and causes the motor to move less and / or differently than the movement corresponding to the applied current, or not to move at all. This often causes undesirable heat generation in the motor.

[0007] However, heat generation in the motor may occur even at low currents. For example, while driving on a straight road, a vehicle driver tends to perform minor steering operations including unconscious steering actions, or tends to slowly drift to one side alternately left and right. In such cases, the restoring torque generating device can be activated by a slight displacement of the steering handle, but no actual steering operation is performed. As a result, the operating current of the electric motor of the restoring torque generating device remains applied for a long time with the same electrical phase of the motor. As a result, individual parts of the motor may overheat.

[0008] Therefore, a technique for avoiding or at least reducing at least one of the aforementioned drawbacks is desirable. Summary of the Invention Problems to be Solved by the Invention

[0009] Accordingly, there are provided a steering apparatus according to claim 1, a steer-by-wire steering system according to claim 17, and a vehicle according to claim 18. Means for Solving the Problems

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

[0011] Thus, a compact implementation of the restoring torque generating device in the steering device is facilitated. Also, the integration of at least one electrical, optical and / or other type of supply line used for the steering handle and / or one or more interface functional members arranged in the steering system is improved. Further, heat generation of the motor of the restoring torque generating device can be avoided or reduced.

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

[0013] The gear ratio is preferably selected such that a slight displacement of the steering handle, particularly a displacement that causes the operation of the restoring torque generating device, corresponds to a switching between different electrical phases of the motor. Also, the gear ratio is preferably selected such that normal steering maneuvers do not correspond to an overly high rotational speed of the motor where undesirable noise of the motor is likely to occur.

[0014] The steering device may further include at least a partially hollow steering column that extends through the hollow core of the motor and the hollow central region of the gear.

[0015] The motor can 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 further be configured to rotate at least partially the steering wheel according to the current driving situation. More precisely, in semi - automatic and / or fully - automatic driving vehicles, the motor may be configured to rotate at least partially the steering wheel according to the turning of the vehicle. Even more precisely, during a transfer operation where the operation changes from an automatic or semi - automatic driving state to a manual driving state, or vice versa, that is, during the transfer situation where the driver hands over the steering to the system, or vice versa, the motor can rotate the steering wheel.

[0017] The gear can be configured to at least partially overlap the motor radially with respect to the axis of the steering device. Additionally or alternatively, the gear can be configured to at least partially overlap the motor axially along the axis of the steering device.

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

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

[0020] The rotor can be integrally formed with the inner gear member of the gear. Accordingly, it is possible to reduce or avoid the extension of the gear in the axial direction toward the steering wheel exceeding the extension of the motor.

[0021] The outer gear member can be configured to be rotatably fixed to the steering wheel. In this case, the intermediate gear member can be configured to be rotatable and axially fixed with respect to at least a partially hollow steering column and / or stator.

[0022] Alternatively, the intermediate gear member can be configured to be rotatably fixed to the steering wheel. In this case, the outer gear member can be configured to be rotatable and axially fixed with respect to at least a partially hollow steering column and / or stator.

[0023] The intermediate gear member and / or the inner gear member can be configured to at least partially surround the motor in the radial direction. Additionally or alternatively, the intermediate gear member and / or the inner gear member can be configured to at least partially surround the motor in the axial direction.

[0024] In an embodiment of a steering apparatus in which the gear includes a harmonic drive gear, the intermediate gear member can include a flex spline of the harmonic drive gear. Further, the inner gear member can include a wave generator of the harmonic drive gear rotatably disposed within the flex spline, and the outer gear member can include a circular spline of the harmonic drive gear.

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

[0026] The restoring torque generating device may further include at least one cooling device configured to cool the motor when the motor is operating.

[0027] The steering device may further include at least one electrical and / or optical interface functional member disposed on the steering wheel and / or within the steering system. The electrical wiring, optical wiring, and / or optical path of the at least one electrical and / or optical interface functional member may extend at least partially within the hollow core of the motor and / or within the hollow central region of the gear.

[0028] The at least one electrical and / or optical interface functional member may include at least one of a heating means for the steering wheel, a display, a lighting means, an airbag, or a control means.

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

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

[0031] According to another aspect, a motor vehicle is provided. The motor vehicle includes a steer-by-wire steering system as currently provided.

Brief Description of the Drawings

[0032] Further details, advantages, and objects of the present invention will become apparent from the drawings and the detailed description.

FIG. 1A-2B

FIG. 3

FIG. 4

DETAILED DESCRIPTION OF THE INVENTION

[0033] FIG. 1A schematically and exemplarily shows a steering device 100a, particularly for use in a motor vehicle. The steering device 100a includes a steering wheel 110 rotatably mounted about an axis A. By rotating the steering wheel 110 about the axis A, a user provides a steering input to the steering device 100a. In the illustrated example, the steering wheel 110 is supported by a steering column 115 of the steering device 100a and is rotatably mounted to the steering column 115 via a steering wheel bearing 112. The steering column 115 can be configured to be rigidly attached to the chassis of a motor vehicle in which the steering device 100a is used, for example, as part of a steer-by-wire steering system.

[0034] The steering device 100a further includes a restoring torque generating device 120a. The restoring torque generating device 120a is configured to apply a restoring torque to the steering handle 110 that at least partially cancels the rotation of the steering handle 110 when the user provides a steering input via 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 rotatably fixed to the steering column 115, and the rotor 134 of the motor 130 is rotatably fixed to the steering handle 110 via the gear 140a. Therefore, the torque generated by the motor 130 is transmitted to the steering handle 110 via the gear 140a, and as a result, a torque is generated between the steering handle 110 and the steering column 115.

[0035] The motor 130 has a hollow core 136. Also, the gear 140a has a hollow central region 142. Therefore, the restoring torque generating device 120a allows for the provision of a hollow conduit H that extends through the hollow core 136 of the motor 130 and the hollow central region 142 of the gear 140a. In the illustrated example, the hollow conduit H extends coaxially with the axis A of the steering device 100a through the steering column 115.

[0036] The hollow conduit H can accommodate the electrical wiring or optical wiring and / or optical path 192 of the electrical and / or optical interface functional member 190, as well as any other type of supply line, in the hollow conduit H, thus facilitating the arrangement of one or more electrical and / or optical interface functional members 190 disposed on the steering handle 110.

[0037] Therefore, the hollow conduit H facilitates a compact and robust arrangement of the electrical, optical, or any other type of supply means of the interface functional member disposed on the steering handle 110.

[0038] At least one electrical and / or optical interface functional member 190 includes, for example, heating means for the steering wheel 110, a display for outputting graphic information to the user, lighting means (such as decorative illumination, an illuminated logo, or lighting means for a control functional member disposed on the steering wheel 110), an airbag housed in some examples of the steering wheel 110, or any type of control means such as one or more control buttons, a control wheel, a touch-sensitive control element, etc. Separate from the electrical wiring or optical wiring that can be housed in the hollow conduit H, the hollow conduit H can also form part of the optical path of the light propagating within the hollow conduit H as part of an optical projection towards the steering wheel 110.

[0039] The steering device 100a further includes a sensor device 180a. The sensor device 180a is configured to detect a steering input provided by the user via the steering wheel 110 and generate a sensor signal indicating the detected steering input. The sensor device 180a is adapted to detect one or more physical characteristics (such as the steering angle or movement of the steering wheel 110 relative to the steering column 115 or the chassis of the motor vehicle to which the steering device 100a is attached) of the steering input provided via the steering wheel 110 and generate a sensor signal corresponding to the detected one or more physical characteristics. The sensor signal is output by the sensor device 180a to a control unit (for example, the control unit of a steer-by-wire steering system of a motor vehicle). Based on the sensor signal, the control unit generates, in some examples, a control signal and outputs it to the motor 130 so as to at least partially cancel out the detected steering input. For example, the control signal for the motor 130 is generated such that the voltage applied to the motor 130 increases in response to an increase in the steering angle input via the steering wheel 110.

[0040] In some examples, the sensor signal is also configured to be used by a control unit to determine a corresponding control signal that is output to one or more steering actuators of the steering system.

[0041] Gear 140a is a strain wave gear. Gear 140a includes an inner gear member in the form of a wave generator 150. The wave generator 150 is rotatably disposed with respect to the steering column 115, and the wave generator 150 is attached to the steering column 115 via a first wave generator bearing 152 and a second wave generator bearing 154. The wave generator 150 is driven by a motor 130. For this purpose, the wave generator 150 is connected to the rotor 134 of the motor 130. Outside the wave generator 150, the wave generator 150 engages with the inner surface of an intermediate member of the gear 140a in the form of a flex spline 160a via a flex spline bearing 168.

[0042] The flex spline 160 has flexibility with respect to a cross section. Also, in the illustrated example, the flex spline 160a is rotatably fixed with respect to the steering column 115. The wave generator 150 has an outer circumference with a cam shape similar to an elliptical shape. Therefore, the rotation of the wave generator 150 due to the operation of the motor 130 causes a deformation of the elliptical shape of the cross section of the flex spline 160a, and the deformation of the elliptical shape propagates while rotating along the outer circumference of the flex spline 160a.

[0043] Gear 140a further includes an outer gear member in the form of a circular spline 170a. In the illustrated example, the circular spline 170a is rotatably fixed to the steering handle 110. Also, the toothed outer profile 162a on the outside of the flex spline 160a engages with the toothed inner profile 172a of the circular spline 170a. The cam shape of the wave generator is such that the toothed outer profile 162a and the toothed inner profile 172a engage near the apex region of each cam, while the toothed outer profile 162a and the toothed inner profile 172a disengage in a region away from the apex region of each cam as an effect of the deformation of the cross-section of the flex spline 160a. The difference in the number of teeth included in the toothed outer profile 162a and the toothed inner profile 172a causes relative rotation between the flex spline 160a and the circular spline 170a when the wave generator 150 is moving. In the illustrated example, since the flex spline 160a is rotatably fixed, the relative rotation between the flex spline 160a and the circular spline 170a causes rotation of the steering wheel 110 relative to the steering column 115.

[0044] Gear 140a is configured such that the gear ratio is 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, more preferably in the range of 28:1 to 32:1.

[0045] The gear ratio within the aforementioned range has been found to be advantageous with respect to avoiding overheating of the motor 130, which results from the continuous application of current to the same electrical phase of the motor 130 when there is, for example, a minute input angle (commonly occurring during long driving on a straight road). The gear ratio within the above-described range ensures that electrical phase switching occurs even for a slight general minute input angle. That is, the gear ratio is large enough so that even a slight change in the input angle at the steering handle 110 generally corresponds to an angle of the rotor 134 of the motor 130 that exceeds at least one phase switching.

[0046] Also, the gear ratio within the above-described range has been found to be advantageous with respect to avoiding undesirable noise of the motor 130 caused by, for example, the high rotational speed of the motor 130 in general steering operation. In general steering operation, noise occurs when the input angle at the steering wheel 110 corresponds to an angle of the rotor 134 of the motor 130 that exceeds an excessively large rotational speed according to the gear ratio. That is, the gear ratio within the above-described range is advantageously small in order to avoid an excessively high rotational speed of the motor 130 in general driving situations.

[0047] The gear 140a is further configured to partially overlap the motor 130 in the radial direction R and surround the motor 130. In this way, it facilitates a compact arrangement of the steering device 100. In the illustrated example, the gear 140a also overlaps 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.

[0048] 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 integrally formed with the rotor 134 of the motor 130. In this case, the additional wave generator bearings 152, 154 may be omitted. Also, in some examples, the gear 140a does not extend beyond the motor 130 in the direction towards the steering wheel 110. In this way, it further facilitates a compact arrangement of the restoring torque generating device 120a.

[0049] The steering device 100a further includes at least one cooling device 122a. The cooling device 122a cools the motor 130, particularly when the motor 130 is operating. A simple implementation of the cooling device 122a includes ventilation holes or ventilation grids disposed in the flexpline 160a that allow for the exhaust of warm air from the interior of the flexpline 160a and replacement by cold air from the outside. In another example, the cooling device 122a further includes a fan driven by the motor 130 that increases the exchange of air between the interior and exterior of the flexpline 160a and / or between the interior and exterior of the wave generator 150. In another example of the cooling device 122a, additional or other means are provided for transporting heat from the motor 130 towards the outside of the steering device 100a.

[0050] In the example shown in FIG. 1A, the circular spline 170a is rotatably fixed to the steering wheel 110, and the flexpline 160a is rotatably fixed to the steering column 115 and the stator 132. In another example, as shown in FIG. 1b, the steering device 100b includes a restoring torque generating device 120b having a gear 140b, the flexpline 160b is rotatably fixed to the steering wheel 110, and the circular spline 170b is rotatably fixed to the steering column 115 and the stator 132. The direction of the combined movement of the steering wheel 110 with respect to the direction of the motor 130 in the steering device 100b is opposite to the direction of the combined movement of the steering wheel 110 with respect to the direction of the motor 130 in the steering device 100a. Accordingly, the operation of the motor 130 is adjusted accordingly. Also, when determining the dimensions of either of the gears 140a, 140b, the effective gear ratio of the strain wave gear changes depending on whether the gear output is performed via the circular spline or via the flexpline. In the latter case, the nominal gear ratio, i.e., n:1, is applied, whereas in the former case, it should be considered that the effective gear ratio increases by 1 with respect to the nominal gear ratio, i.e., (n + 1):1.

[0051] The steering device 100b further includes an externally toothed profile 162b of the flexspline 160b, an internally toothed profile 172b of the circular spline 170b, a cooling device 122b, and a sensor device 180b. Subject to the aforementioned differences between the gears 140a and 140b, these features functionally and structurally correspond to the respective elements 162a, 172a, 122a, 180a of the steering device 100a, as can be understood from FIGS. 1A and 1B. In the example shown in FIG. 1B, the sensor device 180b is configured to detect the relative movement between the flexspline 160b and the steering column 115.

[0052] In the examples shown in FIGS. 1A and 1B, each of the steering devices 100a, 100b includes a steering column 115 that extends through a hollow core 136 and a hollow central region 142 of the gears 140a, 140b. In other examples, the steering devices 100a, 100b do not include a steering column 115. Instead, in some examples, the stator 132 is attached to a substrate, and the gears 140a, 140b and the steering handle 110 are flanged to each other and connected to the rotor 134 without additional support by a steering column.

[0053] FIG. 2A schematically and illustratively shows a steering device 200a according to another example, particularly for use in a motor vehicle. The above description regarding the steering device 100a shown in FIG. 1A applies correspondingly to the steering device 200a shown in FIG. 2A, unless otherwise stated or implicitly apparent from the context. The same reference numerals as in FIG. 1A indicate the same or similar features that serve the same purpose.

[0054] The steering device 200a includes a restoring torque generating device 220a that includes an electric motor 130 and a gear 240a. The gear 240a includes a planetary gear. In the illustrated arrangement, the sun gear 250 forms an inner gear member of the gear 240a that is driven by the motor 130. A device 260a of one or more planetary gears that are rotatably attached to the carrier and each have a toothed profile 262a constitutes an intermediate gear member. A ring gear 270a having an inner toothed profile 272a constitutes an outer gear member of the planetary gear 240a.

[0055] The description of the strain wave gear 140a in FIG. 1A is applicable corresponding to the planetary gear 240a in FIG. 2A. In particular, in the steering device 200a, the ring gear 270a is rotatably fixed to the steering wheel 110, and a device 260a of one or more planetary gears that are rotatably attached to the carrier is rotatably fixed to the steering column 115 and the stator 132. Further, 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, on the condition of structural conformity to the gear 240a.

[0056] In another example, as shown in FIG. 2b, the steering device 200b includes a restoring torque generating device 220b having a gear 240b, a device 260b of one or more planetary gears that are rotatably attached to the carrier is rotatably fixed to the steering wheel 110, and the ring gear 270b is rotatably fixed to the steering column 115 and the stator 132.

[0057] The steering device 200b further includes a toothed profile 162b in each planetary gear, an inner toothed profile 272b of the ring gear 270b, a cooling device 222b, and a sensor device 180b. Subject to the aforementioned differences between the gears 240a and 240b, these features functionally and structurally correspond to the respective elements 262a, 272a, 222a, 180a of the steering device 200a, as understood from FIGS. 2A and 2B. In the example shown in FIG. 2B, the sensor device 180b is configured to detect the relative movement between the device 260b of one or more planetary gears rotatably attached to the carrier and the steering column 115.

[0058] In some examples of the steering devices 200a, 200b, the sun gear 250 is arranged separately from the rotor 134 of the motor 130. In other examples of the steering devices 200a, 200b, the sun gear 250 is integrally formed with the rotor 134 of the motor 130.

[0059] FIG. 3 schematically and exemplarily shows a steer-by-wire steering system 300, particularly for use in a motor vehicle. The steer-by-wire steering system 300 includes a steering device 310. The steering device 310 is a steering device described in relation to the steering devices 100a, 100b, 200a, 200b shown in FIGS. 1A to 2B.

[0060] The steer-by-wire steering system 300 further includes a control unit 320. The control unit 320 is operably connected to the steering device 310. The control unit 320 includes a processing unit and is configured to receive sensor signals from the sensor device of the steering device 310. The sensor signals indicate the steering input provided by the user in the steering device 310. The control unit 320 is also configured by the processing unit to generate a control signal for operating the motor of the restoring torque generator of the steering device 310 based at least in part on the received sensor signals, and 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 generator based on additional information such as the current speed of the motor vehicle, the current inclination of the motor vehicle, the current terrain, the spin of the wheels, etc.

[0061] Furthermore, the control unit 320 is configured by the processing unit to generate a control signal for operating one or more steering actuators 330 of the motor vehicle based at least in part on the received sensor signals. The control unit 320 is further configured to output the generated control signal to one or more steering actuators 330.

[0062] Figure 4 schematically and exemplarily shows a motor vehicle 400. The motor vehicle 400 includes a steer-by-wire steering system 402 described in relation to the steer-by-wire steering system 300 shown in FIG. 3. In particular, the steer-by-wire steering system 402 includes a steering device 410, a control unit 420, and one or more steering actuators 430. The steering device 410 is a steering device described in relation to the steering devices 100a, 100b, 200a, 200b shown in FIGS. 1A to 2B. The control unit 420 is a control unit described in relation to the control unit 320 of the steer-by-wire steering system 300 shown in FIG. 3.

Claims

1. A steering device (100a, 100b, 200a, 200b, 310, 410) for use in a motor vehicle (400), especially for use in a steer-by-wire steering system (300, 402), wherein the steering device (100a, 100b, 200a, 200b, 310, 410) comprises: A steering handle (110) rotatable about an axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410); A restoring torque generating device (120a, 120b, 220a, 220b) coupled to the steering handle (110) and configured to generate a torque that at least partially cancels the rotation of the steering handle (110); The restoring torque generating device (120a, 120b, 220a, 220b) comprises: A motor (130) having a hollow core (136) coaxial with the axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410); A gear (140a, 140b, 240a, 240b) coupled to the motor (130) and configured to transmit the 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 the gear ratio is in the range of 20:1 to 100:

1. A steering device characterized by this.

2. 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. The steering device according to Claim 1.

3. The steering device according to claim 1 or claim 2, further comprising at least a partially hollow steering column (115) that extends through the hollow core (136) of the motor (130) and the hollow central regions (142, 242) of the gears (140a, 140b, 240a, 240b).

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

5. The gears (140a, 140b, 240a, 240b) are configured to at least partially overlap the motor (130) in the radial direction (R) with respect to the axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410) and / or at least partially overlap the motor (130) in the axial direction along the axis (A) of the steering device (100a, 100b, 200a, 200b, 310, 410). The steering device according to any one of the preceding claims.

6. The gears (140a, 140b, 240a, 240b) include harmonic gears (140a, 140b) and / or planetary gears (240a, 240b). The steering device according to any one of the preceding claims.

7. The gears (140a, 140b, 240a, 240b) include inner gear members (150, 250) configured to be driven by the motor (130), at least one intermediate gear member (160a, 160b, 260a, 260b), and outer gear members (170a, 170b, 270a, 270b). The at least one intermediate gear member (160a, 160b, 260a, 260b) engages with the outer surface of the inner gear member (150, 250) and engages with the inner surface of the outer gear member (170a, 170b, 270a, 270b). The steering device according to claim 5 or claim 6.

8. The outer gear members (170a, 270a) are configured to be rotatably fixed to the steering handle (110), and the intermediate gear members (160a, 260a) are configured to be rotatably and axially fixed to the at least partially hollow steering column (115) and / or the stator (132), respectively. The steering device according to claim 7, which is combined with at least one of claims 3 and 4.

9. The intermediate members (160b, 260b) are configured to be rotatably fixed to the steering handle (110), and the outer gear members (170b, 270b) are configured to be rotatably and axially fixed to the at least partially hollow steering column (115) and / or the stator (132), respectively. The steering device according to claim 7, which is combined with at least one of claims 3 and 4.

10. The intermediate gear members (160a, 160b) and / or the inner gear member (150) are configured to at least partially surround the motor (130) in the radial direction (R) and / or the axial direction. The steering device according to any one of claims 7 to 9, which is combined with claim 5.

11. The gears (140a, 140b, 240a, 240b) include strain wave gears (140a, 140b), the intermediate gear members (160a, 160b, 260a, 260b) are provided with flexsplines (160a, 160b), the inner gear members (150, 250) are provided with a wave generator (150) rotatably disposed within the flexsplines (160a, 160b), and the outer gear members (170a, 170b, 270a, 270b) are provided with circular splines (170a, 170b) of the strain wave gears (140a, 140b). The steering device according to any one of claims 7 to 10, which is combined with claim 6.

12. The gears (140a, 140b, 240a, 240b) include planetary gears (240a, 240b), the inner gear members (150, 250) include sun gears (250), the intermediate gear members (160a, 160b, 260a, 260b) include a device (260a, 260b) of one or more planetary gears rotatably attached to a carrier, and the outer gear members (170a, 170b, 270a, 270b) include ring gears (270a, 270b) of the planetary gears (240a, 240b). The steering device according to any one of claims 7 to 10, when combined with claim 6.

13. The restoring torque generating devices (120a, 120b, 220a, 220b) further include at least one cooling device (122a, 122b, 222a, 222b) configured to cool the motor (130) when the motor (130) is operating, and / or The steering device according to any one of the preceding claims further includes at least one sensor device (180a, 180b) configured to detect a steering input provided by a user via the steering handle (110) and generate a sensor signal indicating the detected steering input.

14. The steering device according to any one of the preceding claims further includes at least one electrical and / or optical interface functional member (190) disposed on the steering handle (110). The electrical wiring, optical wiring, and / or optical path (192) of the at least one electrical and / or optical interface functional member (190) extends at least partially within the hollow core (136) of the motor (130) and / or within the hollow central region (142, 242) of the gears (140a, 140b, 240a, 240b). Optionally, the at least one electrical and / or optical interface functional member (190) includes at least one of a heating means, a display, an illumination means, an airbag, or a control means of the steering handle (110).

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

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

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