Steer-by-wire steering system with off-axis steering system support column provided with a steering wheel rotation limiting device

Abstract

The present disclosure relates to a steering system (10) comprising a rotatable steering wheel hub (14), a torque feedback device (44) comprising an electric motor having a rotor (46) and a stator (48), the rotor (46) being attached to the steering wheel hub (14) and the stator (48) being fixed to a non-rotatable component (48) of the steering system (10), a steering system support column (24) comprising an off-axis section (28) having a first longitudinal axis (LI) offset from a rotational axis (A) and an alignment section (26) having a second longitudinal axis (L2) corresponding to the rotational axis (A). The steering wheel hub (14) is rotatably mounted on the alignment section (26) and axially spaced apart from the off-axis section (28). A steering wheel rotation limiting device (52) is attached to the off-axis section (28) and engages the steering wheel hub (14).

Description

TECHNICAL FIELD

[0001] The present invention relates to a steer-by-wire system for a vehicle, in particular a motor vehicle, comprising an off-axis steering system support column provided with a steering wheel rotation limiting device. BACKGROUND

[0002] In the motor vehicle and truck industry, steer-by-wire systems are increasingly being focused on and used, in which mechanical components are replaced by mechatronic configurations. The progress towards fully electric and autonomous vehicles further promotes the development of steer-by-wire steering systems and increases the demand for inventive concepts.

[0003] One particular sub-category of steer-by-wire systems relates to steer-by-wire steering systems, which aim to replace the traditional mechanical components for transmitting the driver's steering commands from the steering wheel to the wheels with mechatronic configurations. Such mechatronic steer-by-wire configurations can partially or completely dispense with a direct or indirect mechanical connection between the steering wheel and the steered wheels. Instead of using mechanical power transmission, the steering commands are detected by sensor devices and transmitted in the form of control signals to mechatronic actuators configured to execute the steering commands via a control unit.

[0004] Steer-by-wire configurations open up completely new possibilities in terms of installation space, assembly of the steering system, safety and design concepts.

[0005] A steer-by-wire system is known, for example, from document US 2020 / 0070871 A, which discloses a vehicle steering wheel assembly comprising a steering wheel, a control component, a rotation measuring component for measuring a rotation state of the steering wheel, and a road feel simulator for applying a resistance torque to the rotation of the steering wheel according to the rotation state of the steering wheel. A steering column is arranged below the steering wheel, wherein an upper end of the steering column is connected to the steering wheel and a lower end of the steering column is connected to the road feel simulator. The road feel simulator is fixed to a vehicle body. Both the rotation measuring component and the road feel simulator are connected to the control component, which controls the road feel simulator according to the measurement data of the rotation measuring component to apply a resistance torque to the rotation of the steering wheel.

[0006] Furthermore, document JP 2019-214360 A discloses a steer-by-wire type power steering device, which is provided with a specific operating range limit adjusting device for replacing a given mechanical end stop present in conventional steering systems.

[0007] Steer-by-wire systems of the prior art generally have a complex structure and are limited in terms of their functionality as well as their suitability and adaptability to different vehicle requirements.

[0008] It is an object of the present invention to provide a steering system which has improved features and overcomes at least some of the disadvantages of the prior art.

[0009] In particular, it is an object of the present application to provide a structurally optimized steer-by-wire system, in particular taking into account a reduced space requirement, robustness and reliability of the steering system and simple assembly.

[0010] These objects are achieved by the subject matter of the independent claims. Preferred embodiments and preferred features are specified in the dependent claims and in the following description. SUMMARY

[0011] The present application relates to a steering system for a vehicle, more precisely to a steer-by-wire system.

[0012] The steering system can comprise a steering wheel hub connected or connectable with a steering wheel. The steering wheel hub rotates about a rotation axis. Thus, the steering wheel connected therewith also rotates about the rotation axis together with the steering wheel hub. In particular, the steering wheel hub can be rotatably mounted on a steering system support column.

[0013] The steering system can comprise a steering wheel, which preferably comprises a gripping portion.

[0014] The steering wheel can be directly or indirectly mechanically attached to the steering wheel hub by a fixing element. For example, the fixing element can be a bolt, a screw, a rivet, a nut, an adhesive and / or swaging (extrusion and / or deformation).

[0015] The steering system can comprise a torque feedback device comprising an electric machine having a rotor and a stator with stator windings, the rotor being fixedly attached to the steering wheel hub so as to rotate about the rotation axis together with the steering wheel hub, and the stator being fixedly attached to a non-rotatable component of the steering system. In other words, non-rotatable means that the stator is rotationally stationary or rotationally fixed relative to the vehicle body.

[0016] The rotor can be an outer rotor and the stator can be an inner stator.

[0017] The fixing element can be arranged at a different radial position (i.e. radial height) relative to the rotation axis than the stator windings.

[0018] The steering system can comprise a rigid steering system support column comprising an off-axis section having a first longitudinal axis offset and preferably parallel to the rotation axis, and comprising an aligned section having a second longitudinal axis corresponding to the rotation axis. Corresponding to the rotation axis can also be described as aligned with or coaxial to the rotation axis. The steering wheel hub can be rotatably mounted on the aligned section, such that it can at least partially overlap the aligned section in an axial direction. The off-axis section can be axially spaced apart or displaced relative to the steering wheel hub.

[0019] The off-axis section and the alignment section can form an entirety and be connected by a connecting portion. The connecting portion is a rigid portion which also forms an entirety, i.e. in one piece, with the off-axis section and the alignment section.

[0020] The steering system can comprise a steering wheel rotation limiting device for mechanically limiting the rotation of the steering wheel hub and thus of the steering wheel connected thereto. The steering wheel rotation limiting device can be configured to limit the rotatability of the steering wheel hub around the rotation axis in both circumferential directions. The steering wheel rotation limiting device can be configured to still allow the steering wheel hub to rotate more than 360°. The steering wheel rotation limiting device can be arranged radially offset and preferably adjacent to the steering wheel hub.

[0021] The steering wheel rotation limiting device can comprise a base fixed to the non-rotatable component of the steering system or to another non-rotatable component. The base comprises two axially opposite end stop surfaces. The steering wheel rotation limiting device can comprise a sliding element which axially slides relative to the base and relative to the steering wheel hub parallel to the rotation axis between the two opposite end stop surfaces. In other words, the sliding element can slide back and forth between the two opposite end stop surfaces.

[0022] The sliding element can comprise a protrusion which engages a helical groove formed on a circumferential surface, preferably an outer circumferential surface, of the steering wheel hub such that a rotation of the steering wheel hub causes an axial movement of the sliding element. Thus, an abutment of the sliding element with one of the two end stop surfaces prevents a further axial movement of the sliding element in one direction and thus a rotation of the steering wheel hub.

[0023] The steering wheel rotation limiting device can be attached to the off-axis section via the base of the steering wheel rotation limiting device and can engage the steering wheel hub via the sliding element. Thus, the steering wheel rotation limiting device can axially extend towards the steering wheel hub.

[0024] According to an aspect, a steering system for a vehicle comprises a steering wheel hub connected or connectable with a steering wheel, wherein the steering wheel hub and thus the steering wheel connected or connectable therewith rotates around a rotation axis.

[0025] The steering system comprises a torque feedback device comprising an electric machine having a rotor and a stator. The rotor is attached to the steering wheel hub so as to rotate with the steering wheel hub around the rotation axis and the stator is fixed to a non-rotatable component of the steering system.

[0026] The steering system comprises a steering system support column comprising an off-axis section having a first longitudinal axis which deviates from and preferably is parallel to the rotation axis, and comprising an aligned section having a second longitudinal axis which corresponds to the rotation axis. Corresponding to the rotation axis can also be described as being aligned with or coaxial to the rotation axis. The steering wheel hub is rotatably mounted on the aligned section, such that it can at least partially overlap the aligned section in axial direction. More precisely, the steering wheel hub can be rotatably mounted on an outer peripheral surface of the aligned section. The off-axis section is axially spaced apart from the steering wheel hub. The steering system support column can be rigid and can form an integral whole, i.e. in one piece.

[0027] The steering system comprises a steering wheel rotation limiting device for limiting the rotation of the steering wheel hub. In particular, the steering wheel rotation limiting device is configured to at least mechanically limit or prevent the rotation of the steering wheel hub around the rotation axis in both circumferential directions. Thus, the steering wheel rotation limiting device is configured to mechanically limit or prevent the rotation of a steering wheel connected with the steering wheel hub. The steering wheel rotation limiting device can still allow the steering wheel hub and the steering wheel to rotate more than 360°. The steering wheel rotation limiting device is attached to the off-axis section via a base of the steering wheel rotation limiting device and engages the steering wheel hub via a sliding element. Thus, the steering wheel rotation limiting device axially extends towards the steering wheel hub and the sliding element radially extends towards the steering wheel hub. Preferably, the steering wheel rotation limiting device can only be attached to the off-axis section of the steering system support column.

[0028] The respective steering system support column provides a new and advantageous structural design which is technically advantageous in view of the space requirement, the adjustability to the ergonomics of the driver and the reduced torque generation / transmission due to friction and inertia.

[0029] The combination of the steering system support column and the steering wheel rotation limiting device facilitates a structurally optimized configuration, in particular in view of the reduced space requirement, the robustness and reliability of the mechanical end stop integration and the simple assembly of the steering system.

[0030] Furthermore, the steering system support column having the off-axis section and the aligned section and the structure of the steering wheel rotation limiting device together allow for an optimized integration and attachment of the steering wheel rotation limiting device.

[0031] The off-axis section can be connected in one piece with the aligned section by a connecting portion extending transversely to the first longitudinal axis and the second longitudinal axis.

[0032] The alignment section of the steering system support column can be a non-rotatable component to which the stator is attached. Thus, the torque feedback device can be arranged in the area in which the steering wheel hub is located and close to the steering wheel, preferably directly on the steering wheel hub. This eliminates the need for a reduction gear train and shafts and reduces unwanted friction and inertia. Thus, the system efficiency can be improved.

[0033] In an embodiment, the steering system support column can not be rotatable about its first longitudinal axis, but can be translationally displaceable along its first longitudinal axis relative to the vehicle body. Thus, the steering system support column can allow for adjustability of the steering system according to the ergonomic needs of the driver. The steering system support column can preferably form an inner member of a tubular telescoping device which is axially displaceably mounted in an outer member of the tubular telescoping device, i.e. translationally displaceable relative to the outer member. The steering system support column can be configured to be non-rotatable and non-pivotable relative to the outer member. The outer member can connect the steering system support column with the vehicle body.

[0034] According to an embodiment, the steering system can comprise an electronic control unit for at least controlling the torque feedback device and / or for receiving and transmitting sensor information, in particular information from a steering wheel angle sensor of the steering system.

[0035] The electronic control unit can be arranged within the off-axis section of the steering system support column. Thus, installation space can be used efficiently.

[0036] The base of the steering wheel rotation limiting device can cover an opening in the off-axis section of the steering system support column which provides access to the motor phase connection and / or the steering wheel angle sensor connection which connect the motor and / or the at least one sensor with the electronic control unit. The sensor can be a steering wheel angle sensor. Thus, the steering wheel rotation limiting device, in particular the detachably attached steering wheel rotation limiting device, can enable accessibility of the electrical connections for repair and maintenance purposes and can at the same time safely protect the electrical connections and components from damaging environmental influences.

[0037] The base of the steering wheel rotation limiting device can be attached to the off-axis section of the steering system support column by screws, bolts, rivets or adhesives, or can be welded to the off-axis section of the steering system support column. Attachment by screws or bolts can provide detachable attachment on the steering system.

[0038] In an embodiment, the rotor can be an outer rotor and the stator can be an inner stator. In this case, the rotor can be attached to the inner peripheral surface of the steering wheel hub. The stator can be attached to the outer surface of the steering system support column, more precisely to the outer peripheral surface of the alignment section. The outer rotor electric machine of the torque feedback device and its direct arrangement on the steering wheel hub and the alignment section eliminates the need for a reduction gear train and shafts and reduces unwanted friction and inertia. Thus, the system efficiency can be improved and the installation space requirement can be reduced.

[0039] According to an embodiment, the base of the steering wheel rotation limiting device can comprise two axially opposite end stop surfaces and the sliding element can axially slide relative to the base and relative to the steering wheel hub parallel to the rotation axis between the two opposite end stop surfaces.

[0040] The sliding element can comprise a protrusion, in particular a helical ridge, which engages a helical groove formed on the outer peripheral surface of the steering wheel hub, such that a rotation of the steering wheel hub causes an axial movement of the sliding element and such that an abutment of the sliding element with one of the two end stop surfaces prevents a further movement of the sliding element in one direction and thus a further rotation of the steering wheel hub in one direction.

[0041] The base can comprise a compartment formed therein, which accommodates the sliding element, thereby inhibiting a radial movement of the sliding element in a direction away from the steering wheel hub and a lateral movement of the sliding element transversely to its axially displaceable direction. The compartment can only allow an axial movement of the sliding element between the two opposite end stop surfaces.

[0042] The base can be arranged radially adjacent to the steering wheel hub, such that the base and the outer peripheral surface of the steering wheel hub completely enclose the compartment.

[0043] The steering system can be configured such that in a state or position of the sliding element abutting one of the two opposite end stop surfaces, the protrusion is still spaced apart from both end portions of the helical groove, preferably by a defined distance or a defined section of the helical groove. Thus, the rotation constraint of the steering wheel hub is not caused by the interaction of a portion of the protrusion with an end portion of the helical groove, but by the abutment of the sliding element surface with one of the two end stop surfaces. Thus, compared to known solutions, the abutment surface area can be increased, which prevents damage to the steering system, in particular to the helical groove and the protrusion, even under the influence of strong external forces.

[0044] In an embodiment, the torque feedback device can be configured to increase the torque feedback level when the minimum distance between the sliding element and one of the two end stop surfaces falls below a predetermined threshold. In this case, the rotation of the steering wheel hub / steering wheel can be slowed down to a certain extent before the sliding element comes into full abutment with one of the two end stop surfaces and suddenly stops the further rotation of the steering wheel hub / steering wheel. The threshold can be defined in relation to each of the two end stop surfaces.

[0045] According to an aspect, a steering system for a vehicle comprises a steering wheel hub connected or connectable with a steering wheel, wherein the steering wheel hub and thereby the steering wheel connected or connectable therewith rotates around an axis of rotation.

[0046] The steering system comprises a torque feedback device comprising an electric machine having a rotor and a stator, the rotor being attached to the steering wheel hub so as to rotate with the steering wheel hub around the axis of rotation, and the stator being fixed to a non-rotatable component of the steering system.

[0047] The steering system comprises a steering wheel rotation limiting device for limiting the rotation of the steering wheel hub. In particular, the steering wheel rotation limiting device is configured to mechanically limit or prevent the rotation of the steering wheel hub around the axis of rotation in both circumferential directions. Thus, the steering wheel rotation limiting device is configured to at least mechanically limit or prevent the rotation of the steering wheel connected with the steering wheel hub. The steering wheel rotation limiting device can still allow the steering wheel hub and the steering wheel to rotate more than 360°. The steering wheel rotation limiting device is arranged radially offset from the steering wheel hub and preferably in the vicinity of the steering wheel hub. The steering wheel rotation limiting device comprises a base fixed to a non-rotatable component or preferably another non-rotatable component of the steering system. The base comprises two axially opposite end stop surfaces with respect to a longitudinal axis parallel to the axis of rotation. The steering wheel rotation limiting device further comprises a sliding element axially sliding with respect to the base and with respect to the steering wheel hub parallel to the axis of rotation. The sliding element slides back and forth between the two opposite end stop surfaces.

[0048] The sliding element comprises a protrusion which engages a helical groove formed on a circumferential surface of the steering wheel hub such that a rotation of the steering wheel hub causes an axial movement of the sliding element and such that an abutment of the sliding element with one of the two end stop surfaces prevents a movement of the sliding element and a rotation of the steering wheel hub. The circumferential surface of the steering wheel hub provided with the helical groove can be an outer circumferential surface. More precisely, when the steering wheel hub is rotated, the interaction and engagement of the protrusion and the helical groove causes the helical groove to drag the protrusion and thus displace the sliding element. The sliding element can then slide, unless it is prevented by one of the two end stop surfaces. An abutment of the sliding element with one of the two end stop surfaces prevents a further movement of the sliding element in one direction and, thus, by the interaction between the protrusion and the helical groove, also a further rotation of the steering wheel hub in one rotational direction. Thus, an abutment of the sliding element with one of the two end stop surfaces limits / constrains / stops the rotational movement of the steering wheel hub and the steering wheel fixedly connected therewith. In other words, the steering wheel rotation limiting device defines and constrains a maximum rotation angle of the steering system around the rotational axis.

[0049] A steering wheel rotation limiting device which limits the rotation of the steering wheel hub based on an abutment of the sliding element with one of the two opposite end stop surfaces while allowing the steering wheel hub to rotate beyond 360° allows to avoid an oversized electric motor of the torque feedback device, since the electric motor does not need to provide a full stoppage torque.

[0050] A steering wheel rotation limiting device which constrains the rotation of the steering wheel hub based on an abutment of the sliding element with one of the two opposite end stop surfaces embodies a robust and reliable solution for providing a mechanical end stop function in a steer-by-wire steering system which does not comprise any natural end stop structure.

[0051] Furthermore, the complexity of the base and the sliding element configuration is low and can be easily manufactured and attached to the steering system.

[0052] A steering system comprising such a steering wheel rotation limiting device can be flexibly integrated in different vehicles and can be simply adapted to different vehicle requirements.

[0053] The steering system can comprise a steering wheel.

[0054] In an embodiment, the base can comprise a compartment formed therein, which compartment accommodates the sliding element, thereby inhibiting or preventing radial movement of the sliding element in a direction away from the steering wheel hub and inhibiting or preventing lateral movement of the sliding element transversely to its axial movability direction. In other words, the compartment can be configured to allow axial movement of the sliding element only between two opposite end stop surfaces. The compartment can be partly complementary to the sliding element so as to prevent radial movement of the sliding element in a direction away from the steering wheel hub and to prevent lateral movement of the sliding element transversely to its axial movability direction. The compartment can be a cuboid recess having five side surfaces, wherein two surfaces define the two end stop surfaces. Only the side of the cuboid recess facing the steering wheel hub is not closed by a side surface, but is open to receive the sliding element and to allow the sliding element (the protrusion) to engage with the helical groove.

[0055] The base can be arranged radially adjacent to the steering wheel hub, such that the outer peripheral surface of the base and the steering wheel hub completely enclose the compartment.

[0056] According to an embodiment, the steering system can be configured such that in a state or position in which the sliding element abuts one of the two opposite end stop surfaces, the protrusion is still spaced apart from the two end portions of the helical groove, preferably by a defined distance or a defined section of the helical groove. Thus, the rotation constraint of the steering wheel hub is not caused by the portion of the protrusion interacting with the end portions of the helical groove, but by the abutment of the sliding element surface with one of the two end stop surfaces. Thus, compared to known solutions, the abutment surface area can be increased, which prevents damage to the steering system, in particular to the helical groove and the protrusion, even under the influence of strong external forces.

[0057] The sliding element can have a substantially rectangular cross-section. The protrusion can be a helical ridge protruding from the sliding element towards the steering wheel hub. The helical ridge can be adapted to the helical groove, in particular to the pitch of the helical groove. The helical ridge can be substantially complementary to a portion of the helical groove.

[0058] The axial width of the sliding element can be adapted according to one or more of the following parameters: the length of the helical groove, the pitch of the helical groove, the distance between the two opposite end stop surfaces, and the circumference of the steering wheel hub. By adapting or selecting the axial width of the sliding element, the maximum travel distance of the sliding element between the two end stop surfaces, i.e. the maximum axial movability, can be defined. Thus, by simply replacing the sliding element and adapting its axial width as well as the dimensions and geometry of the protrusion, the steering wheel rotation limiting device can be flexibly used for different vehicle configurations.

[0059] The steering wheel rotation limiting device can be attached to the non-rotatable component or preferably other non-rotatable component of the steering system by screws, bolts, rivets or adhesives or can be welded to the non-rotatable component or other non-rotatable component of the steering system. Attachment by screws or bolts can be advantageous in that the steering wheel rotation limiting device can thus be detachably mounted on the steering system.

[0060] In an embodiment, the base of the steering wheel rotation limiting device can cover an opening in the non-rotatable component or other non-rotatable component, which opening provides access to an electrical connection that connects the electric motor and / or at least one sensor together with the electronic control unit. The sensor can be a steering wheel angle sensor. Thus, the steering wheel rotation limiting device, in particular a detachably attached steering wheel rotation limiting device, can enable accessibility of the electrical connection for repair and maintenance purposes and can at the same time safely protect the electrical connection and components from damaging environmental influences.

[0061] According to an embodiment, the steering system can further comprise a steering system support column. The steering system support column can be configured to connect the steering wheel hub and the steering wheel with the vehicle body. The steering system support column can be rigid. The steering system support column can comprise an off-axis section having a first longitudinal axis that is offset and preferably parallel to the rotation axis. The steering system support column can comprise an aligned section having a second longitudinal axis that corresponds to the rotation axis. In other words, corresponding to the rotation axis can mean that the second longitudinal axis is aligned / coaxial with the rotation axis.

[0062] The respective steering system support column provides a new and advantageous structural design that is technically advantageous in view of the space requirement, adjustability to the ergonomics of the driver and reduced friction and inertia torque generation / transmission.

[0063] The combination of the described steering system support column design and the steering wheel rotation limiting device facilitates a structurally optimized configuration, in particular in view of the reduced space requirement, robustness and reliability of the mechanical end stop integration and simple assembly of the steering system.

[0064] Furthermore, the steering system support column with the off-axis section and the aligned section and the structure of the described steering wheel rotation limiting device together allow for an optimized integration and attachment of the steering wheel rotation limiting device.

[0065] The steering system support column can form an entirety, i.e. one piece. In particular, the off-axis section can be connected to the aligned section in an entirety by a connecting portion extending transversely to the first longitudinal axis and the second longitudinal axis.

[0066] The alignment section of the steering system support column can be a non-rotatable component to which the stator is attached, and the off-axis section can be a further non-rotatable component to which the base of the steering wheel rotation limiting device is attached. Thus, the torque feedback device can be arranged in the area where the steering wheel hub is located and close to the steering wheel, preferably directly on the steering wheel hub. This eliminates the need for a reduction gear train and shaft, and reduces unwanted friction and inertia. Thus, the system efficiency can be improved.

[0067] In an embodiment, the steering system support column can not rotate about its first longitudinal axis, but can be translationally displaced relative to the vehicle body along its first longitudinal axis. Thus, the steering system support column can allow for adjustability of the steering system according to the ergonomic needs of the driver. The steering system support column can preferably form an inner member of a tubular telescoping device. In this case, the steering system support column can be translationally displaced relative to an outer member. The steering system support column can be non-rotatable and non-pivotable relative to the outer member. The outer member can connect the steering system support column with the vehicle body.

[0068] According to an embodiment, the steering wheel hub can be rotatably mounted on the alignment section, such that it can at least partially overlap the alignment section in the axial direction. The off-axis section can be axially spaced apart from the steering wheel hub.

[0069] In an embodiment of the steering system, the rotor can be an outer rotor and the stator can be an inner stator. In this case, the rotor can be attached to an inner circumferential surface of the steering wheel hub. The stator can be attached to an outer surface of the steering system support column, more precisely to an outer circumferential surface of the alignment section.

[0070] In an embodiment, the torque feedback device can be configured to increase the torque feedback level when the minimum distance between the sliding element and one of the two end stop surfaces falls below a predetermined threshold value. In this case, the rotation of the steering wheel hub / steering wheel can be slowed down to a certain extent before the sliding element comes into full abutment with one of the two end stop surfaces and suddenly stops the further rotation of the steering wheel hub / steering wheel. A threshold value can be defined relative to each of the two end stop surfaces.

[0071] According to an aspect, a steering system for a vehicle comprises a steering wheel hub connected or connectable with a steering wheel, wherein the steering wheel hub and thereby the steering wheel connected or connectable therewith rotates about an axis of rotation.

[0072] The steering system comprises a steering system support column comprising an off-axis section having a first longitudinal axis which is offset and preferably parallel to the axis of rotation, and comprising an aligned section having a second longitudinal axis which corresponds to the axis of rotation. Corresponding to the axis of rotation can also be described as being aligned with or coaxial to the axis of rotation. The off-axis section and the aligned section form an entirety and are connected by a connecting portion. The connecting portion also forms an entirety with the off-axis section and the aligned section. Thus, the off-axis section, the aligned section and the connecting portion are formed as a rigid one-piece component. The steering wheel hub is rotatably mounted on the aligned section and thus at least partially overlaps the aligned section in axial direction. The off-axis section is axially spaced apart from the steering wheel hub.

[0073] The steering system comprises a torque feedback device comprising an electric motor having a rotor and a stator. The rotor is fixedly attached to the steering wheel hub so as to rotate with the steering wheel hub around the axis of rotation. The stator is non-rotatably fixed to the aligned section of the steering system support column.

[0074] Preferably, the aligned section can form a hub element which is stationary with respect to the rotor and the steering wheel hub and which carries the inner stator of the outer rotor electric motor.

[0075] The new and advantageous structural design of the steering system support column forming an entirety, i.e. one piece, provides an optimized use of installation space while allowing for simple adjustability to the ergonomics of the driver and while reducing friction and inertia due to torque generation / transmission at the same time, the steering system support column comprising an off-axis section and an aligned axis section and a torque feedback device arranged on the aligned section.

[0076] Thus, the combination of the described steering system support column design and the torque feedback device contributes to a structurally optimized configuration.

[0077] The connecting portion which also forms an entirety with the off-axis section and the aligned section can extend transversely to both the first longitudinal axis and the second longitudinal axis.

[0078] The off-axis section, the aligned section and / or the connecting portion can be tubular. In particular, each of the off-axis section, the aligned section and the connecting portion can be tubular. The off-axis section, the aligned section and / or the connecting portion can at least partially have a substantially rectangular or circular cross-section. Alternatively, the off-axis section, the aligned section and / or the connecting portion can have any other cross-sectional shape. For example, the off-axis section, the aligned section and / or the connecting portion can have an elliptical or polygonal cross-section. A polygonal cross-section can be advantageous in view of providing some flat surfaces to provide an angular reference between the axial sliding portion and the fixed portion of the telescoping device in order to prevent rotation relative to each other around the first longitudinal axis. The cross-sectional shape of the off-axis section, the aligned section and the connecting portion can be the same or different.

[0079] In an embodiment, the steering system support column can be attached to the vehicle body via a vehicle support column. The off-axis section of the steering system support column can be mounted in the vehicle support column so as to move translationally along its first longitudinal axis, non-rotatably and non-pivotably relative to the vehicle support column. This means that in this embodiment, the steering system support column and all components supported thereon are respectively displaceable / non-displaceable relative to the vehicle support column. The steering system support column can be attached to the vehicle support column by means of a bracket, an axial adjustment element and / or a vertical adjustment element.

[0080] The support of the off-axis section of the steering system support column in the vehicle support column can be implemented at a first end of the steering system support column opposite the second end of the steering system support column on which the torque feedback device is arranged (i.e. spaced apart from the alignment section).

[0081] This configuration allows for the adjustability of the steering system to the ergonomics of the driver, while eliminating the need for a reduction gear train and shaft, thereby reducing friction and inertia during torque generation and transmission of the steer-by-wire system.

[0082] The steering system support column can form an inner member of a tubular telescoping device, and the vehicle support column can form an outer member of the tubular telescoping device. The inner member is axially mounted in the outer member of the tubular telescoping device and displaced translationally.

[0083] The vehicle support column and thus the steering system (i.e. all other system components mounted / attached to the steering system support column) can be adjusted relative to the vehicle body by pivoting and / or radial displacement relative to the vehicle body. The pivotability and / or radial displaceability can involve movement of at least a portion of the steering system support column along at least one cross axis transverse to the first longitudinal axis.

[0084] According to an embodiment, the steering system support column can comprise an opening, which is preferably arranged in the off-axis section or in the connecting portion, which opening provides access to the motor phase connection and / or the steering wheel angle sensor connection, which connect the motor and / or at least one sensor with the electronic control unit. The sensor can be a steering wheel angle sensor. Thus, the steering wheel rotation limiting device, in particular the detachably attached steering wheel rotation limiting device, can enable the accessibility of the electrical connections for maintenance and servicing purposes, and can at the same time safely protect the electrical connections and components from damaging environmental influences.

[0085] According to an embodiment, the steering system can comprise an electronic control unit for at least controlling the torque feedback device and / or for receiving and transferring sensor information, e.g. information from a steering wheel angle sensor. The electronic control unit can be arranged within the off-axis section of the steering system support column, preferably in a region adjacent to or after the connection portion. In this case, the electronic control unit can be in close proximity to the stator winding of the torque feedback electric machine and / or to one or more sensors, e.g. a rotation angle sensor for measuring the rotation of the rotor of the electric machine.

[0086] In an embodiment, the steering system can comprise auxiliary components arranged within the alignment section of the steering system support column and thus within the stator of the torque feedback electric machine. The auxiliary components can comprise an airbag module, a switchgear controller, a driver display device and / or a wiring harness. By arranging the auxiliary components within the steering system support column, the installation space can be used efficiently, i.e. the total installation space required by the steering system can be reduced.

[0087] In an embodiment, the rotor can be an outer rotor and the stator can be an inner stator. Thus, the torque feedback device can be an outer rotor electric torque feedback machine. In this case, the rotor can be attached to the inner circumferential surface of the steering wheel hub. The stator can be attached to the outer surface of the steering system support column, more precisely to the outer circumferential surface of the alignment section. The outer rotor electric machine of the torque feedback device and its direct arrangement on the steering wheel hub and the alignment section eliminates the need for a reduction gear train and shafts and reduces unwanted friction and inertia. Thus, the system efficiency can be improved and the installation space requirement can be reduced.

[0088] According to an embodiment, the alignment section of the steering system support column can be provided with a protruding flange portion providing a first bearing surface for a first bearing device arranged between the steering system support column and the steering wheel hub. Preferably, the protruding flange portion can be arranged in a transition area between the alignment section and the connection portion, i.e. an end portion of the alignment section facing away from the steering wheel to which the steering system is connected or connectable. The protruding flange portion provides a circular ring-shaped first bearing surface. By the protruding flange portion, the outer diameter of the main portion of the alignment section can be minimized while still supporting a steering wheel hub having a substantially larger inner diameter.

[0089] The alignment section of the steering system support column can comprise a toroidal portion providing a toroidal second bearing surface for a second bearing device arranged between the steering system support column and the steering wheel hub. Preferably, the toroidal portion can be arranged at least in a region adjacent to or behind a region of the steering wheel connected or connectable with the steering system, in other words at least in a region facing away from the off-axis section and the connecting portion. By means of the toroidal portion, the outer shape / profile of the main portion of the alignment section can be freely chosen while still rotatably supporting the steering wheel.

[0090] The first bearing device and the second bearing device enable rotatable support of the steering wheel hub and the steering wheel connected therewith on the steering system support column.

[0091] In an embodiment, the steering system can comprise a steering wheel rotation limiting device for at least mechanically limiting the rotation of the steering wheel hub around the rotation axis in both circumferential directions. The steering wheel rotation limiting device can be attached to the off-axis section via a base portion of the steering wheel rotation limiting device and can engage the steering wheel hub via a sliding element.

[0092] The base portion of the steering wheel rotation limiting device comprises two axially opposite end stop surfaces and the sliding element axially slides relative to the base portion and relative to the steering wheel hub parallel to the rotation axis between the two opposite end stop surfaces. The sliding element can comprise a protrusion, in particular a helical ridge, which engages a helical groove formed on an outer circumferential surface of the steering wheel hub such that a rotation of the steering wheel hub causes an axial movement of the sliding element and such that an abutment of the sliding element with one of the two end stop surfaces prevents a further movement of the sliding element and thus a further rotation of the steering wheel hub.

[0093] The base portion of the steering wheel rotation limiting device can overlap the protruding flange portion and thus the first bearing surface in the axial direction relative to the rotation axis. Thus, an advantageous compact design of the steering system structure can be achieved.

[0094] According to an aspect, a steering system for a vehicle comprises a steering wheel and a steering wheel hub, wherein the steering wheel is mechanically attached to the steering wheel hub by means of a fixing element. Preferably, the steering wheel is directly and fixedly attached to the steering wheel hub. The fixing element can be a bolt and / or a screw. Preferably, a total of three to ten screws can be arranged equidistantly around the rotation axis of the steering wheel and the steering wheel hub.

[0095] The steering system comprises a steering system support column, wherein the steering wheel hub is rotatably mounted on the steering system support column such that the steering wheel and the steering wheel hub rotate around the rotation axis.

[0096] The steering system comprises a torque feedback device comprising an electric machine with an outer rotor and an inner stator with stator windings. The outer rotor is attached to the steering wheel hub so as to rotate together with the steering wheel hub around an axis of rotation. Preferably, the outer rotor is fixed to an inner circumferential surface of the steering wheel hub. The inner stator is non-rotatably fixed to the steering system support column. Preferably, the inner stator is fixed to an outer circumferential surface of the steering system support column.

[0097] The fixing elements are arranged at a different radial position relative to the axis of rotation than the stator windings. In other words, when viewed with respect to the axis of rotation, the fixing elements are arranged at a different radial height than the stator windings, i.e. the fixing elements have a different radial distance from the axis of rotation than the stator windings.

[0098] Providing the torque feedback device with an outer rotor electric machine and arranging the fixing elements at a different radial position relative to the axis of rotation than the stator windings allows for an advantageous compact design of the steer-by-wire steering system, which reduces the required installation space.

[0099] A portion of the fixing elements can axially overlap a portion of the stator windings relative to the axis of rotation. In particular, a portion of each of the fixing elements or only a portion of one or specific fixing elements can axially overlap a portion of the stator windings relative to the axis of rotation. This arrangement is possible by arranging the fixing elements at a different radial position relative to the axis of rotation than the stator windings. Thus, at least a portion of the fixing elements can be arranged parallel to the stator windings, which further contributes to a compact construction of the steering system.

[0100] According to an embodiment, the steering system can comprise a first bearing device arranged between the steering system support column and the steering wheel hub for enabling rotation of the steering wheel hub relative to the steering system support column. The steering system can comprise a second bearing device arranged between the steering system support column and the steering wheel hub for enabling rotation of the steering wheel hub relative to the steering system support column. The second bearing device can be axially spaced apart from the first bearing device relative to the axis of rotation. The second bearing device can be closer to the steering wheel than the first bearing device.

[0101] The first bearing device can be arranged at a different radial position relative to the axis of rotation than the second bearing device. Again, the wording "at a different radial position" can also be described as a different radial height when viewed with respect to the axis of rotation, i.e. having a different radial distance from the axis of rotation. Arranging the second bearing device at a different radial position relative to the axis of rotation than the first bearing device, i.e. closer to the axis of rotation, allows for an overlapping arrangement of further components parallel to the second bearing device, which further contributes to a compact design.

[0102] The fixing element can be arranged at a different radial position relative to the rotational axis than the first bearing device; and / or the fixing element can be arranged at a different radial position relative to the rotational axis than the second bearing device. This arrangement can also enable an overlapping / parallel arrangement of the steering system components, which further contributes to a compact design of the steering system and a reduced installation space requirement.

[0103] In an embodiment, the steering system support column, in particular the alignment section of the steering system support column, can be provided with an outwardly protruding flange portion providing a toroidal first bearing surface for the first bearing device. The protruding flange portion protruding from the outer peripheral surface of the steering system support column is preferably arranged in a transition area between the alignment section and the connecting portion of the steering system support column. By means of the protruding flange portion, the outer diameter of the main portion of the alignment section can be minimized while still supporting the steering wheel hub having a substantially larger inner diameter.

[0104] The steering system support column, in particular the alignment section of the steering system support column, can be provided with a toroidal portion providing a toroidal second bearing surface for the second bearing device. The toroidal portion providing the second bearing surface can have a substantially smaller outer diameter than the protruding flange portion. The toroidal portion can be provided at least in a region adjacent to the steering wheel or in a region behind the steering wheel, i.e. at least in a region facing away from the off-axis section. By means of the toroidal portion, the outer shape / profile of the main portion of the alignment section can be freely chosen while still rotatably supporting the steering wheel.

[0105] In an embodiment, the fixing element can axially overlap the second bearing device relative to the rotational axis. The fixing element can partially or completely overlap the second bearing device. This further contributes to a compact design of the steering system and a reduced installation space requirement.

[0106] The steering wheel hub can be provided with an inwardly protruding flange portion providing a counter bearing surface for the second bearing device, which counter bearing surface substantially opposes the second bearing surface. Inwardly protruding means that the inwardly protruding flange portion protrudes towards the steering system support column, i.e. towards the rotational axis. The counter bearing surface forms a toroidal portion for supporting the second bearing device.

[0107] The inwardly protruding flange portion of the steering wheel hub can be formed in a region of the steering wheel hub axially arranged between the steering wheel and the motor of the torque feedback device. Thus, the motor can be covered by the inwardly protruding flange portion towards the steering wheel.

[0108] The blind hole can be formed in the steering wheel hub in the region of the inwardly protruding flange portion, preferably in the inwardly protruding flange portion, wherein the fixing element extends into the blind hole for fastening the steering wheel to the steering wheel hub. The blind hole can be internally provided with a thread in order to secure the fixing element in the form of a screw or bolt therein.

[0109] In an embodiment, the fixing element can be arranged at substantially the same radial position as the outer rotor of the torque feedback device with respect to the rotation axis. This configuration can limit the radial extension of the steering system in the region of the torque feedback device.

[0110] According to an embodiment, the steering wheel can comprise a rigid steering wheel armature comprising a through-hole, wherein the fixing element extends through the through-hole into the steering wheel hub for fastening the steering wheel to the steering wheel hub. Preferably, the through-hole can be aligned with the blind hole in the steering wheel hub.

[0111] According to an embodiment, the steering system support column can comprise an off-axis section having a first longitudinal axis that is offset and preferably parallel to the rotation axis, and can comprise an aligned section having a second longitudinal axis that corresponds to the rotation axis. The off-axis section and the aligned section can form an entirety and be connected by a connecting portion. The steering wheel hub can be rotatably mounted on the aligned section and thus at least partially overlap the aligned section in axial direction, while the off-axis section is axially spaced apart from the steering wheel hub. The stator can be non-rotatably fixed to the aligned section of the steering system support column.

[0112] In an embodiment, the steering system can comprise a steering wheel rotation limiting device for limiting the rotation of the steering wheel hub. In particular, the steering wheel rotation limiting device can be configured to at least mechanically limit or prevent the rotation of the steering wheel hub about the rotation axis in both circumferential directions. Thus, the steering wheel rotation limiting device can be configured to mechanically limit or prevent the rotation of the steering wheel connected with the steering wheel hub. The steering wheel rotation limiting device can still allow the steering wheel hub and the steering wheel to rotate more than 360°. The steering wheel rotation limiting device can be attached to the off-axis section via a base of the steering wheel rotation limiting device and can engage the steering wheel hub via a sliding element. Thus, the steering wheel rotation limiting device can axially extend towards the steering wheel hub and the sliding element can radially extend towards the steering wheel hub. Preferably, the steering wheel rotation limiting device can be attached to the off-axis section of the steering system support column only.

[0113] Although some of the features, functions, embodiments, technical effects and advantages have been described for one aspect, it is to be understood that these features, functions, embodiments, technical effects and advantages can be combined with each other, also for other embodiments and aspects. BRIEF DESCRIPTION OF DRAWINGS

[0114] To better understand how the invention is implemented and to illustrate how it is carried out, reference will now be made to the accompanying drawings by way of example only, wherein similar reference numerals always denote corresponding elements or parts.

[0115] In the attached diagram:

[0116] Figure 1 A schematic cross-sectional view of a steering system according to an embodiment of the present invention is shown.

[0117] Figure 2 It shows Figure 1 A schematic side view of the steering system.

[0118] Figure 3 It shows Figure 1 A schematic 3D diagram of the steering system.

[0119] Figure 4 It shows Figure 1 Another schematic perspective view of the steering system.

[0120] Figure 5 It shows Figure 1 Another schematic 3D view of the steering system.

[0121] Figure 6 It shows Figure 1 Other schematic perspective views of the steering system.

[0122] Figure 7 A to Figure 7 C illustrates the steering wheel rotation limiting device of the steering system in schematic disassembled, assembled, and installed states.

[0123] Figure 8 A to Figure 8 F shows a schematic diagram of a steering wheel rotation limiting device used to illustrate the functional principle of the steering wheel rotation limiting device.

[0124] Figure 9 A to Figure 9 Figure C shows a schematic diagram of a steering wheel rotation limiting device and a steering wheel hub, used to illustrate the functional principle of the steering wheel rotation limiting device. Detailed Implementation

[0125] Several examples of embodiments of the invention will be explained in more detail with the aid of the following embodiments shown in the accompanying drawings and / or described below.

[0126] Figures 1 to 6 A schematic diagram of a steering system 10 for a road vehicle according to an embodiment of the present invention is shown. Figures 1 to 6As shown, the steering system 10 is a steer-by-wire steering system, which does not have a direct mechanical connection to transfer steering commands of a driver from a steering wheel 12 of the steering system 10 to wheels (not shown) of the vehicle. Instead, the mechanical connection is replaced by electromechanical devices.

[0127] In addition to the steering wheel 12, the steering system 10 comprises a steering wheel hub 14 which is mechanically connected with the steering wheel 12. The steering wheel hub 14 and the steering wheel 12 are not rotatable relative to each other, but can be rotated together about a rotation axis A. The steering wheel 12 is detachably attached to the steering wheel hub 14 in a non-rotatable manner by means of fixation elements 16 in the form of screws. More precisely, the steering wheel 12 is provided with an inner armature 18, wherein the fixation elements 16 extend through through-holes 20 of the inner armature 18 into internally threaded blind holes 22 provided in the steering wheel hub 14.

[0128] The steering wheel hub 14 is rotatably supported on a rigid steering system support column 24 of the steering system 10, more precisely on an alignment section 26 of the steering system support column 24. In addition to the alignment section 26, the steering system support column 24 comprises an off-axis section 28 which is formed integrally with the alignment section 26. The off-axis section 28 is axially spaced apart from the alignment section 26 and the steering wheel hub 14, whereas the steering wheel hub 14 overlaps the alignment section 26 and is positioned coaxially therewith. The off-axis section 28 has a first longitudinal axis LI which is offset and parallel to the rotation axis A. The alignment section 26 has a second longitudinal axis L2. The alignment section 26 of the steering system support column 24 is aligned or coaxial with the steering wheel hub 14 and the steering wheel 12, i.e. the second longitudinal axis L2 corresponds to the rotation axis A.

[0129] The off-axis section 28 and the alignment section 26 are formed integrally and are connected by a connecting portion 30 which extends transversely to the first longitudinal axis LI and the second longitudinal axis L2.

[0130] The steering wheel hub 14 is rotatably mounted on the alignment section 26 of the steering system support column 24 by means of a first bearing device 32 and a second bearing device 34 which is axially spaced apart from the first bearing device 32. For example, the first bearing device 32 and / or the second bearing device 34 can be a ball bearing or a roller bearing.

[0131] The first bearing device 32 is supported on a protruding flange portion 36 of the alignment section 26 of the steering system support column 24 which protrudes radially outward from an outer circumferential surface of the alignment section 26. The protruding flange portion 36 provides an annular first bearing surface for supporting the first bearing device 32. The protruding flange portion 36 is arranged in the vicinity of the connecting portion 30, i.e. in a transition area between the alignment section 26 and the connecting portion 30. Thus, the first bearing device 32 is axially located at a first end portion of the alignment section 26 which is oriented towards the connecting portion 30.

[0132] The second bearing device 34 is supported on a toroidal portion 38 of the alignment section 26 of the steering system support column 24. The toroidal portion 38 is formed in the area of the alignment section 26 next to the steering wheel 12 and extends towards the protruding flange portion 36. The circular toroidal portion 38 provides a second bearing surface for the second bearing device 34. Thus, the second bearing device 34 is axially located at a second end portion of the alignment section 26 opposite the first end portion.

[0133] The first bearing device 32 is mounted between the protruding flange portion 36 of the alignment section 26 and the steering wheel hub 14 via a support bushing 40 arranged between the first bearing device 32 and the inner circumferential surface of the steering wheel hub 14.

[0134] The second bearing device 34 is directly mounted between the toroidal portion 38 of the alignment section 26 and the steering wheel hub 14. To this end, the steering wheel hub 14 is provided with an inwardly protruding flange portion 42 which provides an opposite bearing surface for the second bearing device 34. At the same time, the inwardly protruding flange portion 42 covers components located inside the steering wheel hub 14. As Figure 1 shown, the blind hole 22 for receiving the fixation element 16 extends into or through the inwardly protruding flange portion 42.

[0135] The steering system 10 further comprises a torque feedback device 44 comprising an electric machine having a rotor 46 and a stator 48 with stator windings 50. The torque feedback device 44 can be operated to generate a resistive torque against rotation of the steering wheel 12 in order to simulate the resistive torque present in a conventional steering system. In other words, the torque generated by the torque feedback device 44 can counteract the rotational force applied to the steering wheel 12 by the driver.

[0136] In the shown embodiment, the electric machine is an outer rotor electric machine comprising an outer rotor 46 and an inner stator 48. The rotor 46 is fixed to the inner circumferential surface of the steering wheel hub 14. Thus, the rotor 46 rotates together with the steering wheel hub 14 about the rotational axis A. The rotor 46 is non-rotatable relative to the steering wheel hub 14. The stator 48 is fixed to the rotatably stationary, i.e. non-rotatable, alignment section 26 of the steering system support column 24. Thus, the steering wheel hub 14 and the rotor 46 can rotate together with the stator 48 and the alignment section 26.

[0137] The electric machine of the torque feedback device 44 is arranged within the steering wheel hub 14. The torque feedback device 44 is radially enclosed by and thus covered by the steering wheel hub 14 (the inner peripheral surface of the steering wheel hub 14) and the alignment section 26 of the steering system support column 24 (the outer peripheral surface of the alignment section 26). The torque feedback device 44 is axially located between the protruding flange portion 36 of the alignment section 26 and the circular ring portion 38 of the alignment section 26. The torque feedback device 44 is axially enclosed on one side by the protruding flange portion 36 of the alignment section 26, the first bearing device 32 and the support bushing 40, and on the other side by the inwardly protruding flange portion 42 of the steering wheel hub 14 and the second bearing device 3, and thus covered by them.

[0138] The arrangement, configuration and support of the steering wheel hub 14, the steering wheel 12, the torque feedback device 44 and the steering system support column 24 provide a very compact structure. More precisely, as shown in Figure 1 the radial and / or axial arrangement of the individual components is at least partially arranged parallel to each other.

[0139] That is, with respect to the rotation axis A, the fixation element 16 is arranged at a different radial position (i.e. at a different radial height) than the stator winding 50. Thus, the fixation element 16 and the blind hole 22 at least partially overlap the stator winding 50 in axial direction. The stator winding 50 can be arranged closer to the rotation axis A than the fixation element 16.

[0140] Further, with respect to the rotation axis A, the second bearing device 34 is arranged at a different radial position (i.e. at a different radial height) than the stator winding 50 and at a different radial position (i.e. at a different radial height) than the fixation element 16. In the shown embodiment, the fixation element 16 overlaps the second bearing device 34 in axial direction. The second bearing device 34 can be arranged closer to the rotation axis A than the stator winding 50 and can be arranged closer to the rotation axis A than the fixation element 16.

[0141] Further, with respect to the rotation axis A, the first bearing device 32 is arranged at a different radial position (i.e. at a different radial height) than the second bearing device 34 and at a different radial position (i.e. at a different radial height) than the fixation element 16. With respect to the rotation axis A, the first bearing device 32 is arranged at a similar radial position than the stator winding 50. The first bearing device 32 can be arranged closer to the rotation axis A than the stator fixation element 16 and can be arranged further away from the rotation axis A than the second bearing device 34.

[0142] With respect to the rotation axis A, the fixation element 16 is arranged at a similar radial position than the outer rotor 46 of the torque feedback device 44. This limits the radial extension of the steering system 10 in the area of the torque feedback device 44.

[0143] The steering system 10 further comprises a steering wheel rotation limiting device 52 for limiting the rotation of the steering wheel hub 14 and of the steering wheel 12. The steering wheel rotation limiting device 52 is fixed to the steering system support column 24 and is arranged radially offset from the steering wheel hub 14, more precisely adjacent to the outer peripheral surface of the steering wheel hub 14. The steering wheel rotation limiting device 52 is non-rotatable with respect to the steering system support column 24.

[0144] The steering wheel rotation limiting device 52 comprises a base 54 and a sliding element 56 arranged within a compartment 58 formed in the base 54. The sliding element 56 is axially slidable with respect to the base 54 and with respect to the steering wheel hub 14. The sliding element 56 can slide between two opposite end stop surfaces 60, 62 (see Figure 7 A to Figure 9 C of the enclosed drawings). The sliding element 56 comprises a protrusion 64 which engages a helical groove 66 formed on the outer peripheral surface of the steering wheel hub 14. By the interaction of the protrusion 64 and the helical groove 66, the rotation of the steering wheel hub 14 causes an axial movement of the sliding element 56. Likewise, the abutment of the sliding element 56 with one of the two end stop surfaces 60, 62 prevents a further movement of the sliding element 56 in a certain direction and, therefore, a further rotation of the steering wheel hub 14 in a certain rotational direction. Thus, the steering wheel rotation limiting device 52 is configured to constrain the rotation of the steering wheel hub 14 and of the steering wheel 12 connected therewith.

[0145] The base 54 of the steering wheel rotation limiting device 52 is fixed to the off-axis section 28 (see Figures 5 to 9 C of the enclosed drawings) of the steering system support column 24 by means of screws 68. The steering wheel rotation limiting device 52, more precisely the base 54, extends in axial direction from the off-axis section 28 of the steering system support column 24 to the steering wheel hub 14, so that the compartment 58 is arranged between and enclosed by the base 54 and the outer peripheral surface of the steering wheel hub 14.

[0146] The function and further details of the steering wheel rotation limiting device 52 will be described in the text referring to Figure 7 A to Figure 9 C of the enclosed drawings.

[0147] The base part 54 of the steering wheel rotation limiting device 52 covers an opening 70 arranged in the off-axis section 28 of the steering system support column 24. More precisely, the opening 70 is arranged in a further transition area between the off-axis section 28 and the connecting portion 30. For service and maintenance purposes, the opening 70 provides access to a motor phase connection 72 and to an electric steering wheel angle sensor connection 74. The motor phase connection 72 connects the motor of the torque feedback device 44 with a control unit / control electronics 76. The electric steering wheel angle sensor connection 74 connects the steering wheel angle sensor 78 with the control unit / control electronics 76.

[0148] The control unit 76 is arranged within the hollow tubular off-axis section 28 of the steering system support column 24. More precisely, the control unit 76 is arranged in a portion of the off-axis section 28 close to the connecting portion 30 in order to position the control unit 76 and the motor close to each other.

[0149] The steering wheel angle sensor 78 is configured to measure the current steering angle and, thus, to detect the steering command of the driver, which is to be electronically transmitted to the actuator for actuating / steering the wheels in accordance with the command. The steering wheel angle sensor 78 is arranged adjacent to or aside the first bearing device 32.

[0150] The steering system support column 24 forms an inner member of a tubular telescopic device 80. An outer member of the tubular telescopic device 80 is embodied by a vehicle support column 82. In particular, the off-axis section 28 is axially slidably mounted within the outer member / vehicle support column 82 of the tubular telescopic device 80. Thus, the steering system support column 24 is translationally displaceable relative to the vehicle support column 82 and the vehicle body, but is non-rotatable and non-pivotable relative to the vehicle support column 82.

[0151] The steering system support column 24 is connected to the vehicle body (not shown) via the vehicle support column 82 by means of a bracket, an axial adjustment element and a vertical adjustment element 84. Thus, the steering system support column 24 and all components supported thereon are translationally displaceable relative to the first longitudinal axis LI independently of the vehicle support column 82. Furthermore, the steering system support column 24 and all components supported thereon are radially displaceable / pivotable relative to the vehicle body in dependence on the vehicle support column 82, i.e. the adjustability / displaceability of the vehicle support column 82.

[0152] The steering system support column 24 has a hollow tubular shape. The steering system support column 24 is formed as a rigid one-piece component and is preferably made of metal. As Figures 3 to 6As shown, it is shown that at least the off-axis section 28 of the steering system support column 24 has a substantially rectangular cross-section. This shape can be particularly advantageous for accommodating and attaching the control unit 76. Similar to the off-axis section 28, the vehicle support column 82 which forms together with the off-axis section 28 the tubular telescopic device 80 has a substantially rectangular cross-section.

[0153] The connection portion 30 of the steering system support column 24 forms a tapering transition from the off-axis section 28 towards the alignment section 26. The alignment section 26 has a smaller diameter than the off-axis section 28. The alignment section 26 has a substantially circular cross-section.

[0154] As Figure 3 and Figure 5 in combination Figure 1 Further shown, the steering wheel 12 is provided with an interior space 86 for accommodating auxiliary components (not shown), such as airbag modules, switchgear controllers, driver display devices, etc. These auxiliary components as well as other auxiliary components, such as wiring harnesses, can extend into the hollow tubular alignment section 26. Thus, these auxiliary components as well as other auxiliary components can be arranged and / or attached within the alignment section 26 of the steering system support column 24.

[0155] Figure 7 A of Fig. 1 to Figure 9 C of Fig. 1 are used to disclose details about the function and configuration of the steering wheel rotation limiting device 52. Figure 7 A of Fig. 1 shows the components of the steering wheel rotation limiting device 52, respectively, in an exploded view. Figure 7 B of Fig. 1 shows the components of the steering wheel rotation limiting device 52 in an assembled state. Figure 7 C of Fig. 1 shows the steering wheel rotation limiting device 52 mounted to or interacting with the steering wheel hub 14.

[0156] As Figure 7 A to Figure 7 C of Fig. 1, four screws 68 extend through the base 54 in order to securely fix the steering wheel rotation limiting device 52 to the steering system support column 24. The base 54 has a compartment 58 formed therein. Two axially opposite side surfaces of the compartment 58 constitute end stop surfaces 60, 62. The compartment 58 is complementary to the part of the sliding element 56 arranged therein (see Figure 7(B). Therefore, the compartment 58, more precisely, the bottom and side surfaces of the compartment 58, constrain the mobility of the sliding element 56 to axial sliding between the two end stop surfaces 60, 62 (indicated by arrow AS). The two end stop surfaces 60, 62 restrict the sliding of the sliding element 56 in the axial direction. When the sliding element 56 is adjacent to one of the two end stop surfaces 60, 62, further movement in the current direction is prevented, and the sliding element 56 can only move in the other axial direction, i.e., toward the corresponding other end stop surface 60, 62. In the installed state, the surface oriented toward the steering wheel hub 14 is curved and substantially complementary to the corresponding portion of the outer peripheral surface of the steering wheel hub 14.

[0157] The sliding element 56 engages via a protrusion 64 with a helical groove 66 formed in the outer peripheral surface of the steering wheel hub 14. The protrusion 64 is formed as a helical ridge and adapted to the shape and size of the helical groove 66. The sliding element 56 interacts with the steering wheel hub 14 via the helical groove 66. As the steering wheel 12 and thus the steering wheel hub 14 rotate, the sliding element 56 is dragged axially within the compartment 58 according to one of the arrows AS. The sliding element 56 slides until the rotation of the steering wheel hub 14 stops, or until the abutment of the sliding element 56 with one of the two end stop surfaces 60, 62 prevents further movement. Therefore, preventing further axial movement of the sliding element 56 prevents further rotation of the steering wheel hub 14, and thus prevents further rotation of the steering wheel 12 in the direction of rotation, which would cause the sliding element 56 to move further axially toward the end stop surface 60, 62 that is currently preventing further movement.

[0158] like Figure 7 As shown in Figure A, the sliding element 56 has an axial width W. The axial width W of the sliding element 56 determines the free space within the compartment 58 between the sliding element 56 and the end stop surfaces 60, 62. Therefore, by adapting or selecting the axial width W of the sliding element 56, the maximum travel distance (i.e., maximum axial mobility) of the sliding element 56 between the two end stop surfaces 60, 62 is adjustable. Thus, by simply replacing the sliding element 56 and adapting its axial width W, as well as the size and geometry of the protrusion 64, the steering wheel rotation limiting device 56 can be flexibly used in different vehicle configurations. In particular, the axial width W can be selected based on one or more of the following parameters: the length of the helical groove 66, the pitch of the helical groove 66, the distance between the two opposing end stop surfaces 60, 62, and the circumference of the steering wheel hub 14.

[0159] Figure 8 A, Figure 8 B and Figure 9Figure A shows the sliding element 56 adjacent to an end stop surface 60. In this position, the sliding element 56 can only slide in the direction toward the other end stop surface 62. That is, in this position, the steering wheel hub 14 and the steering wheel 12 can only rotate in a specific rotational direction, which causes the sliding element 56 to move toward the other end stop surface 62. Figure 8 C Figure 8 D and Figure 9 Figure B shows a position where the sliding element 56 can slide freely in two axial directions. That is, in this position, the steering wheel hub 14 and the steering wheel 12 can rotate freely in two rotational directions. Figure 8 E, Figure 8 F and Figure 9 C shows the abutment of the sliding element 56 with the other end stop surface 62. In this position, the sliding element 56 can only slide in the direction toward one end stop surface 60. That is, in this position, the steering wheel hub 14 and the steering wheel 12 can only rotate in a specific rotational direction, which causes the sliding element 56 to move toward one end stop surface 60.

[0160] At least as Figure 9 As shown in Figure A, at the position where the sliding element abuts one of the two opposing end stop surfaces, the protrusion 64 remains spaced from the nearest end portion 88 of the helical groove 66. Therefore, the rotational constraint of the steering wheel hub 14 is not caused by the abutment of the protrusion 64 with the end portion 88 of the helical groove 66, but rather by the abutment of the sliding element 56 with one of the two end stop surfaces 60, 62. This robust configuration prevents damage to the steering system 10, particularly to the helical groove 66 and the protrusion 64, even under strong external forces.

[0161] List of reference numerals

[0162] 10 Steering System 50 Stator Winding

[0163] 12 Steering wheel 52 Steering wheel rotation limiter

[0164] 14-inch steering wheel hub 54-inch base

[0165] 16 Fixed elements 56 Sliding elements

[0166] 18 armatures, 58 compartments

[0167] 20 through hole 60 end stop surface

[0168] 22 blind hole 62 end stop surface

[0169] 24 Steering system support column 64 extension

[0170] 26 alignment section 66 helical groove

[0171] 28 off-axis section 68 screw

[0172] 30 connecting portion 70 opening

[0173] 32 first bearing device 72 motor phase connection

[0174] 34 second bearing device 74 steering wheel angle sensor connection

[0175] 36 protruding flange portion 76 control unit

[0176] 38 toroidal portion 78 steering wheel angle sensor

[0177] 40 support bushing 80 tubular telescoping device

[0178] 42 inwardly protruding flange portion 82 vehicle support column

[0179] 44 torque feedback device 84 adjustment element

[0180] 46 rotor 86 inner space

[0181] 48 stator 88 end portion

[0182] L1 first longitudinal axis A rotational axis

[0183] L2 second longitudinal axis AS axial direction

[0184] W axial width

Claims

1. A steering system (10) for a vehicle, comprising: a steering wheel hub (14) connected or connectable with a steering wheel (12), the steering wheel hub (14) being rotatable about an axis of rotation (A); a torque feedback device (44) comprising an electric machine having a rotor (46) and a stator (48), the rotor (46) being attached to the steering wheel hub (14) so as to be rotatable together with the steering wheel hub (14) about the axis of rotation (A), and the stator (48) being fixed to a non-rotatable component (48) of the steering system (10); a steering system support column (24) comprising an off-axis section (28) having a first longitudinal axis (LI) offset from the axis of rotation (A) and an alignment section (26) having a second longitudinal axis (L2) corresponding to the axis of rotation (A), wherein the steering wheel hub (14) is rotatably mounted on the alignment section (26), while the off-axis section (28) is axially spaced apart from the steering wheel hub (14); and a steering wheel rotation limiting device (52) for limiting the rotation of the steering wheel hub (14), the steering wheel rotation limiting device (52) being attached to the off-axis section (28) via a base portion (54) of the steering wheel rotation limiting device (52) and engaging the steering wheel hub (14) via a sliding element (56); wherein the steering wheel rotation limiting device (52) axially extends towards the steering wheel hub (14), and the base portion (54) of the steering wheel rotation limiting device (52) is arranged radially offset from the steering wheel hub (14).

2. The steering system (10) according to claim 1, wherein the first longitudinal axis (LI) is parallel to the axis of rotation (A).

3. The steering system (10) according to claim 1, wherein the off-axis section (28) is integrally connected with the alignment section (26) by a connecting portion (30) extending transversely to both the first longitudinal axis (LI) and the second longitudinal axis (L2).

4. The steering system (10) according to claim 1, wherein the alignment section (26) of the steering system support column (24) is the non-rotatable component to which the stator (48) is attached.

5. The steering system (10) according to claim 1, wherein the steering system support column (24) is non-rotatable but translationally displaceable along the first longitudinal axis (LI), wherein the steering system support column (24) forms an inner member of a tubular telescoping device (80) which is axially displaceably mounted in an outer member (82) of the tubular telescoping device (80).

6. The steering system (10) according to claim 1, further comprising an electronic control unit (76) for at least one of receiving and transmitting sensor information and for controlling the torque feedback device (44). ​ 7. The steering system (10) of claim 6, wherein the electronic control unit (76) is disposed within the off-axis section (28) of the steering system support column (24).

8. The steering system (10) of claim 6, wherein the base (54) of the steering wheel rotation limiting device (52) covers an opening (70) in the off-axis section (28) of the steering system support column (24) that provides access to electrical connections (72, 74) that connect at least one of a sensor (78) and the electric motor with the electronic control unit (76).

9. The steering system (10) of claim 1, wherein the base (54) of the steering wheel rotation limiting device (52) is attached to the off-axis section (28) of the steering system support column (24) by screws (68), bolts, rivets, or adhesive or is welded to the off-axis section (28) of the steering system support column (24).

10. The steering system (10) of claim 1, wherein the rotor (46) is an outer rotor and the stator (48) is an inner stator.

11. The steering system (10) of claim 1, wherein the base (54) of the steering wheel rotation limiting device (52) includes two opposing end stop surfaces (60, 62) and the sliding element (56) axially slides relative to the base (54) and relative to the steering wheel hub (14) parallel to the rotation axis (A) between the two opposing end stop surfaces (60, 62), wherein the sliding element (56) includes a protrusion (64) that engages a helical groove (66) formed on a circumferential surface of the steering wheel hub (14) such that rotation of the steering wheel hub (14) causes axial movement of the sliding element (56) and such that abutment of the sliding element (56) with one of the two end stop surfaces (60, 62) prevents movement of the sliding element (56) and rotation of the steering wheel hub (14).

12. The steering system (10) of claim 11, wherein the base (54) includes a compartment (58) formed in the base that houses the sliding element (56) and thereby inhibits radial movement of the sliding element (56) in a direction away from the steering wheel hub (14) and lateral movement of the sliding element (56) transverse to the axial movement direction (AS) of the sliding element.

13. The steering system (10) of claim 12, wherein the base (54) is disposed radially adjacent to the steering wheel hub (14) such that the base (54) completely encloses the compartment (58) with an outer peripheral surface of the steering wheel hub (14).

14. The steering system (10) of claim 11, wherein the projection (64) is still spaced apart from the end portion (88) of the helical groove (66) in a condition where the sliding element (56) abuts one of the two opposing end stop surfaces (60, 62).

15. The steering system (10) of claim 11, wherein the projection (64) is a helical ridge.

16. The steering system (10) of claim 11, wherein the torque feedback device (44) is configured to increase a torque feedback level when a minimum distance between the sliding element (56) and one of the two end stop surfaces (60, 62) falls below a predetermined threshold.

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