Module for steer-by-wire steering system such system and vehicle

Abstract

The disclosure concerns a module 2 for a steer-by-wire steering system, which includes an input shaft 4 configured to rotate about a rotational axis 6, a reduction gear, and an electric motor. The reduction gear comprises a planetary gearset 10 including a ring gear 12, a sun gear 14, and at least one planet gear 16 mounted on a planet gear carrier 18. The motor shaft of the electric motor and the sun gear are arranged concentrically with the rotational axis of the input shaft. The input shaft is connected to the planet gear carrier, and the electric motor is connected to the sun gear. This module provides for a compact steering system for vehicles.

Description

[0001] Module for Steer-by-Wire Steering System such System and Vehicle

[0002] TECHNICAL FIELD

[0003] The present technical relates to steer-by-wire steering systems. Herein, a module for a steer- by-wire steering system, a steer-by-wire steering system for a vehicle, and a vehicle comprising a steer-by-wire steering system are discussed.

[0004] BACKGROUND

[0005] Steer-by-wire steering systems have been developed as an alternative to traditional mechanical steering systems, which typically include a mechanical connection between the steering wheel and the steered wheels of a vehicle. In a steer-by-wire steering system, there is no mechanical connection between the steering wheel and the steered wheels. Instead, steering input is transmitted electronically to control the steered wheels. This allows for greater flexibility in the design of the steering system and can potentially improve the overall performance and efficiency of a vehicle.

[0006] However, there are several challenges associated with steer-by-wire steering systems. One such challenge is the limitation of steering wheel turns. In a traditional mechanical steering system, the steering wheel is mechanically limited in its rotation by the steering range of the steered wheels, preventing it from turning multiple times and causing damage to the steering system components. In a steer-by-wire steering system, there is no such natural mechanical limitation, which can potentially lead to the steering wheel turning multiple times and reaching a limit for electrical connectors between the steering wheel and other components of the vehicle, causing damage or malfunction.

[0007] Several prior art solutions have been proposed to address these challenges. For example, US 2023 / 109811 describes a rotation limitation module for a steer-by-wire steering system, which includes a housing, a shaft portion, a limiter disk, and first and second detent rings. DE 102019202294 discloses a steering limiting device for a steer-by-wire steering system, which includes a planetary gearset, a sun gear connected to the steering wheel shaft, and at least one stop element fastened to a planet gear carrier.

[0008] Another challenge associated with steer-by-wire steering systems is the design of the steering wheel actuator. The actuator is responsible for providing torque feedback to the steering wheel, simulating the feel of a mechanical steering system. It has been suggested to utilise a worm gear arranged between the steering wheel shaft and a servo motor of the actuator. The use of a worm gear reduction in the steering wheel actuator can cause a servo motor to protrude significantly, making it difficult to build the steering wheel actuator into a vehicle and adjust the steering wheel position. The large volume needed for the displacement of the actuator, including the protruding servo motor, creates challenges in the integration of the steering wheel actuator into a vehicle.

[0009] The solutions of US 2023 / 109811 and DE 102019202294 may not fully address the challenges associated with steer-by-wire systems, and there remains a need for improved designs and mechanisms to limit steering wheel turns, reduce the size and complexity of the steering wheel actuator, and improve the overall efficiency and reliability of steer-by-wire steering systems.

[0010] SUMMARY

[0011] It would be advantageous to achieve a steer-by-wire steering system that is reliable and easily installable in a vehicle. In particular, it would be desirable to provide a compact module for a steer-by-wire steering system. To better address one or more of these concerns, one or more of a module for a steer-by-wire steering system, a steer-by-wire steering system, and a vehicle having the features defined in one or more of the independent claims is provided.

[0012] According to an aspect of the disclosure, a module for a steer-by-wire steering system is provided. This module comprises an input shaft configured to rotate about a rotational axis, a reduction gear, and an electric motor. The reduction gear comprises a planetary gearset including a ring gear, a sun gear, and at least one planet gear mounted on a planet gear carrier. A motor shaft of the electric motor and the sun gear are arranged concentrically with the rotational axis of the input shaft. The input shaft is connected to the planet gear carrier, and the motor shaft of the electric motor is connected to the sun gear.

[0013] Since the reduction gear comprises the planetary gearset and since the input shaft is connected to the planet gear carrier and the motor shaft is connected to the sun gear - a compact module is provided. Thus, the module is easy to fit into a vehicle.

[0014] According to a further aspect, a steer-by-wire steering system for a vehicle is provided. The steer-by wire steering system comprises a module according to any one of aspects and / or embodiments discussed herein. This system is compact since it comprises the herein discussed module and thus, is easy to fit into a vehicle.

[0015] According to a further aspect, a vehicle is provided. This vehicle comprises a steer-by-wire steering system according to any one of aspects and / or embodiments discussed herein. This vehicle benefits from the advantages of the steer-by-wire steering system, including the compact design of the module and thus, an easy fit in the vehicle and an uncomplicated adjusting of a steering wheel position within the vehicle.

[0016] Namely, in a modern vehicle, a position of the steering wheel may be adjustable thus, being positionable to suit a particular driver. Adjusting the position of a steering wheel in a drive-by- wire steering system may require for the steering wheel actuator i.e. , the module, to be displaceable in relation to a fixed structure of the vehicle. Such displacement requires space in the vehicle.

[0017] The herein discussed compact design of the module due to the concentric arrangement of the motor shaft and the sun gear with the rotational axis of the input shaft as well as the motor shaft being connected to the sun gear provides for the module requiring little space e.g., in comparison with a steering wheel actuator comprising a worm gear. Thus, the module is particularly suited for displacement with a limited space.

[0018] The vehicle may be a passenger car, a truck, or any other type of land-based vehicle that requires a steering system.

[0019] In a vehicle in the form of a truck there is limited space between its steering wheel and a front end of the truck. Therefore, the module may be suited for a steer-by-wire steering system of a truck.

[0020] In the steer-by-wire steering system, herein also referred to as the steer-by-wire system, there is no mechanical connection between the steering wheel of the vehicle and steered wheels of the vehicle. Steering input, by turning of the steering wheel, is provided via the steer-by-wire system to the steered wheels. The steering input is transmitted electronically to one or more actuators configured for controlling steering settings of the steered wheels. Thus, the steer-by-wire system is a system in the vehicle that provides at least the functionality and control of an ordinary mechanical steering system.

[0021] In the module, a so-called torque and angle sensor measures the torque applied by a driver of the vehicle to the steering wheel and also detects an angle of rotation of the steering wheel. This sensor provides input to the steer-by wire steering system, one the basis of which input the steered wheels of the vehicle are controlled e.g., steering angles of the steered wheels being controlled. The electric motor, sometimes referred to as servo motor, provides torque feedback to the steering wheel and the driver of the vehicle. The feedback is transmitted via the planetary gearset and the input shaft to the steering wheel. Control input to the electric motor is provided by the steer-by-wire steering system e.g., based on sensors and / or actuators associated with the steered wheels. Thus, the driver receives feedback, inter alia from forces affecting the steered wheels.

[0022] The module forms part of a steering wheel actuator i.e. , the module is configured for providing torque feedback to the steering wheel. Moreover, the module provides for the input shaft and accordingly, the steering wheel to rotate more than one full rotation. This feature is provided by the reduction gear, which increases the range of motion of the steering wheel. As discussed above, herein the reduction gear comprises the planetary gearset.

[0023] In a known manner the planetary gearset includes the ring gear, the sun gear, and the at least one planet gear mounted on the planet gear carrier.

[0024] As mentioned above, the electric motor is connected to the sun gear and the input shaft is connected to the planet gear carrier. The steering wheel is connected to the input shaft, either directly or via a steering wheel shaft.

[0025] Commonly, one or more electric switches, buttons, and / or other electronic control devices are arranged in the steering wheel of a modern vehicle. Accordingly, electric signals from such control devices have to be led via electrical wiring and / or conductors to one or more intended signal receivers within the vehicle.

[0026] Since the steering wheel can be rotated more than one turn, often substantially more, it is not feasible to led electrical wires from the rotatable steering wheel to connection points that are fixed in relation to the vehicle.

[0027] Therefore, a rotary connector assembly may be provided for electrical connection between electrical wiring that rotates with the steering wheel and stationary electrical wiring in the vehicle. The rotary connector assembly may comprise, and / or may be referred to, as a clock spring mechanism. For instance, the rotary connector assembly may be connected to the input shaft.

[0028] Optionally in some examples, the module comprises a limiting mechanism configured for limiting a rotation of the input shaft. This limiting mechanism is arranged at the planetary gearset. In this manner, the steering wheel may be prevented from turning too far, preventing damage or malfunction of the module and / or thereto related components such as the rotary connector assembly.

[0029] Namely, the rotary connector assembly has an angular limitation before it is damaged and / or it ruptures. The limiting mechanism suitably, may be devised to limit the rotation of the input shaft to a rotational angle below the angular limitation of the rotary connector assembly.

[0030] Optionally in some examples, the limiting mechanism comprises at least one first stop element connected to, or forming part of, the at least one planet gear and at least one second stop element fixedly arranged in the module. A rotation of the planetary gearset is stopped when the at least one first stop element makes contact with the at least one second stop element. In this manner, the limiting mechanism may be efficiently implemented.

[0031] Since the rotation of the planetary gearset is stopped, also the rotation of the input shaft is stopped.

[0032] Optionally in some examples, the module comprises a housing, wherein the ring gear is fixed in relation to the housing. In this manner, the ring gear may be arranged fixedly in the module.

[0033] Optionally in some examples, the at least one second stop element is directly or indirectly connected to the housing. In this manner, the at least one second stop element may be fixedly arranged in the module.

[0034] Optionally in some examples, the at least one second stop element is connected to, or forms part of, a flange of the electric motor. In this manner, since the flange of the electric motor is fixed within the module, also, the at least one second stop element may be fixedly arranged in the module.

[0035] Optionally in some examples, the at least one second stop element comprises two second stop elements, each of the second stop elements being arranged at a distance from each other along the ring gear. In this manner, for instance, stopping angles of the input shaft and the steering wheel may be optimised for different types of vehicles and / or contact forces between the at least one first stop element and the at least one second stop element acting on the planetary gearset can be favourably distributed, such a symmetrically distributed about the planetary gearset. Optionally in some examples, the at least one planet gear comprises a first planet gear and a second planet gear, wherein the at least one first stop element comprises one stop element arranged on each of the first and second planet gears. In this manner, a symmetrical and reliable planetary gearset may be provided. This feature may provide a balanced and controlled steering experience.

[0036] Optionally in some examples, the module comprises a rotary connector assembly for electrical wiring, the rotary connector assembly being connected to the input shaft. In this manner, and as discussed above, transmission of electrical signals while enabling the steering wheel to rotate continuously without electrical conductors becoming tangled or disconnected may be ensured.

[0037] Further features of, and advantages will become apparent when studying the appended claims and the following detailed description.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Various aspects and / or embodiments, including particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0040] Fig. 1 illustrates a perspective view of a module of a drive-by-wire steering system with a planetary gearset and an electric motor,

[0041] Fig. 2 shows an electric motor and a limiting mechanism of a module, Figs. 3a - 3d illustrates a limiting mechanism of a planetary gearset, Fig. 4 discloses details of a limiting mechanism,

[0042] Fig. 5 shows a limiting mechanism of a planetary gearset according to an alternative example, and

[0043] Fig. 6 displays an example of a vehicle comprising a steer-by-wire steering system.

[0044] DETAILED DESCRIPTION

[0045] Aspects and / or examples will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity.

[0046] Fig. 1 schematically illustrates a perspective view of a module 2 of a drive-by-wire steering system. The steer-by-wire steering system may be a steer-by-wire steering system 52 as discussed below with reference to Fig. 6. Accordingly, the module 2 is configured to form part of a steering wheel actuator of a vehicle.

[0047] The module 2 includes several components that work together to facilitate the steer-by-wire steering system. The module 2 is a component of the steer-by-wire steering system. It is designed to be compact making it easy to fit into a vehicle 40, see Fig. 6. The module 2 comprises an input shaft 4, a reduction gear 8, and an electric motor 20.

[0048] The reduction gear 8 is a component of the module 2 that increases the number of turns the input shaft 4 and a steering wheel of the relevant vehicle can be turned before hitting an end limit of a steering wheel rotation. This feature increases the range of motion of the steering wheel. The reduction gear 8 comprises a planetary gearset 10, which includes a ring gear 12, a sun gear 14, and at least one planet gear 16 mounted on a planet gear carrier 18. In the example module 2 of Fig. 1, the planetary gearset 10 comprises two planet gears 16.

[0049] In Fig. 1 , for the purpose of clarity, each of the gears 12, 14, 16 is shown without its cogs. Moreover, for the purpose of clarity, the ring gear 12 and the planet gear carrier 18 are drawn with broken lines.

[0050] The planetary gearset 10 is connected to the input shaft 4, enabling the transmission of rotation from the steering wheel to the reduction gear 8 and for efficient transmission of torque and rotation from the electric motor 20 to the steering wheel.

[0051] In more detail about the planetary gearset 10: The ring gear 12 is fixedly arranged in the module 2. The sun gear 14 aligns with the rotational axis 6 of the input shaft 4. The at least one planet gear 16 is mounted on the planet gear carrier 18. Each planet gear 16 rotates in relation to the planet gear carrier 18 about a planet gear rotational axis 46. Moreover, the planet gear 16 rotates with the planet gear carrier 18 within the ring gear 12. The planet gear carrier 18 is connected to the input shaft 4, allowing it to rotate with the input shaft 4. This rotation of the planet gear carrier 18 causes the at least one planet gear 16 to rotate about its planet gear rotational axis 46.

[0052] As in every planetary gearset 10, the ring gear 12 engages with the at least one planet gear 16. The at least one planet gear 16 engages with the ring gear 12 and the sun gear 14. The planet gear carrier 18 supports the at least one planet gear 16. The input shaft 4 is configured to rotate about a rotational axis 6. The input shaft 4 is connected to the planet gear carrier 18 of the planetary gearset 10. This connection allows the input shaft 4 to transmit the rotation from the steering wheel to the planetary gearset 10.

[0053] The sun gear 14 is connected to the electric motor 20 via a motor shaft of the electric motor 20. The electric motor 20 is arranged to transmit torque and rotation to the planetary gearset 10 via the sun gear 14. Since the sun gear 14 aligns with the rotational axis 6 of the input shaft 4, a rotational axis of the motor shaft 22 and the sun gear 14 is concentric with the rotational axis 6 of the input shaft 4.

[0054] The module 2 comprises a housing 30 that encloses and / or supports various components of the module 2. In Fig. 1, the housing 30 is schematically indicated with a dash-dotted line. The electric motor 20 and the ring gear 12 are fixedly arranged in relation to the housing 30.

[0055] According to an example, the ring gear 12 may be an integral part of the housing 30. According to an example, the ring gear 12 and the housing 30 may be a monolithic unit.

[0056] The electric motor 20 is a component of the module 2. For instance, the electric motor 20 may be a brushless DC, permanent magnet motor. The electric motor 20 provides torque feedback to the steering wheel of the relevant vehicle via the planetary gearset 10 and the input shaft 4. As mentioned above, control input to the electric motor 20 is provided by the steer-by-wire system e.g., based on sensors and / or actuators associated with the steered wheels of the vehicle.

[0057] Since the electric motor 20 is connected to the sun gear 14 of the planetary gearset 10, this arrangement contributes to a compact design of the module 2.

[0058] The electric motor 20 comprises a mounting flange 38. The motor mounting flange 38 is configured for mounting the electric motor 20 in the module 2. The mounting flange 38 is fixedly arranged in relation to the housing 30. The mounting flange 38 is configured for direct or indirect connection to the planetary gearset 10. In a direct connection, the mounting flange 38 may be connected to the ring gear 12. An indirect connection may be provided via the housing 30.

[0059] A steering wheel shaft 36 may be provided as an interconnector between the steering wheel of the vehicle and the input shaft 4. In such instances, the steering wheel shaft 36 is fixedly connected to the input shaft 4. The steering wheel shaft 36 transmits rotation applied to the steering wheel to the module 2. Conversely, torque and rotation provided by the module 2 is transmitted via the steering wheel shaft 36 to the steering wheel.

[0060] A torque and angle sensor 32 is a component of the module 2 that measures the torque applied to the input shaft 4 from the steering wheel of the vehicle and detects the angle of rotation of the input shaft 4 as applied from the steering wheel. This sensor 32 provides electric input signals to the steer-by-wire steering system. In the system, the input signals are utilised for controlling the steered wheels of the vehicle. Such torque and angle sensors 32 are known.

[0061] The torque and angle sensor 32 is connected to the input shaft 4.

[0062] In some steer-by-wire systems, a torque and angle sensor may not be required. In such systems the torque and angle sensor 32 may be omitted.

[0063] Further, the module 2 comprises a rotary connector assembly 34 that allows for the transmission of electrical signals from e.g. buttons arranged in the steering wheel to receiving components in the vehicle while enabling the steering wheel to be rotated. This assembly 34 forms an intermediate part between electrical conductors arranged in, and rotating with, the steering wheel and electrical conductors that are stationary in relation to other parts of the vehicle.

[0064] However, the rotary connector assembly 34 cannot be rotated an unlimited number of full rotations i.e. , the rotary connector assembly 34 has a maximum rotational angle that cannot be exceeded if proper function of the rotary connector assembly 34 is to be ensured. For this reason, the module 2 comprises a limiting mechanism, as will be discussed below with reference to Figs 2 - 5.

[0065] The rotary connector assembly 34 is connected to the input shaft 4.

[0066] The steering wheel shaft 36 may be seen to form part of the input shaft 4. Accordingly, the torque and angle sensor 32 and / or the rotary connector assembly 34 may be connected to the steering wheel shaft 36. A physical connection between the steering wheel shaft 36 and the input shaft 4 may be arranged as indicated in Fig. 1 or closer to the planet gear carrier 18, such as between the torque and angle sensor 32 and the rotary connector assembly 34 or between the planet gear carrier 18 and the torque and angle sensor 32. Fig. 2 schematically illustrates an electric motor 20 and a limiting mechanism 24 of a module. The module is a module 2 as discussed herein, inter alia with reference to Fig. 1.

[0067] Accordingly, in the following reference is also made to Fig. 1.

[0068] As discussed above, the module 2 comprises the electric motor 20, which includes a motor shaft 22 that is connected to the sun gear 14 of the planetary gearset 10. In Fig. 2, all components of the planetary gearset 10 except for its sun gear 14 have been omitted for clarity purposes.

[0069] As also discussed above, the module 2 may comprise a rotary connector assembly 34 (not shown in Fig. 2).

[0070] The module 2 includes a limiting mechanism 24 that is configured for limiting a rotation of the input shaft 4. Thus, damage is avoided to the rotary connector assembly 34 due to rotating the steering wheel and the input shaft 4 such that a maximum rotational angle of the rotary connector assembly 34 is exceeded.

[0071] The limiting mechanism 24 is arranged at the planetary gearset 10 and comprises at least one first stop element 26 connected to, or forming part of, the at least one planet gear 16 and at least one second stop element 28 fixedly arranged in the module 2.

[0072] Due to the limiting mechanism 24, the rotation of the planetary gearset 10 is stopped when the at least one first stop element 26 makes contact with the at least one second stop element 28, preventing the steering wheel and the input shaft 4 from being turned further and thus, ensuring that the rotary connector assembly 34 is not rotated too much.

[0073] The at least one first stop element 26 rotates with the at least one planet gear 16 as it rotates within the ring gear 12 until it makes contact with the fixed at least one second stop element 28. Rotation of the planetary gearset 10 and accordingly, of the input shaft 4 is thus, stopped. From this stop position / angle, the steering wheel and the input shaft 4 can only be rotated in an opposite direction. Again, until the at least one first stop element 26 makes contact with the fixed at least one second stop element 28. See also below with reference to Figs. 3a - 5.

[0074] The at least one second stop element 28 is fixedly arranged in the module 2. For instance, the at least one second stop element 28 may be connected to, or form part, of the housing 30. The at least one second stop element 28 may be connected to, or form part, of the ring gear 12, or as shown in Fig. 2, it may be integrated into the motor mounting flange 38 of the electric motor 20. Thus, the at least one second stop element 28 is directly or indirectly connected to the housing 30.

[0075] In the embodiments of Figs. 2, the at least one first stop element 26 comprises two first stop elements 26, one connected to each planet gear 16 and the at least one second stop element 28 comprises two second stop elements 28. The two second stop elements 28 are arranged symmetrically arranged on opposite sides of the motor shaft 22. Since the planet gears 16 are arranged at 180 degrees from each other, each of the two first stop elements 26 make simultaneous contact with a respective of the two second stop elements 28. Thus, the stopping contact forces acting between the two pairs of first and second stop element 26, 28 are symmetrically arranged about the rotational axis 6. This provides an even load on inter alia the components of the planetary gearset 10.

[0076] Figs. 3a - 3d schematically illustrate a limiting mechanism 24 of a planetary gearset 10. The limiting mechanism 24 may be a limiting mechanism 24 as discussed above with reference to Fig. 2. Figs. 3a - 3d shown the planetary gearset 10 in a plan view from a side of the planetary gearset 10, at which side the electric motor is arranged. The planet gear carrier 18 is arranged at an opposite side of the planetary gearset 10 and is indicated with broken lines.

[0077] More specifically, Figs. 3a - 3b show portions of the planetary gearset 10 in different angular / rotational positions as the at least one planet gear 16 rotate along the ring gear 12 from one stop position in a first rotational direction to an opposite stop position in a second rotational direction.

[0078] Again, the at least one first stop element comprises two stop elements 261, 262. A first 261 of the at least one first stop element is connected to, or forms part of, a first planet gear 161 of the at least one planet gear. The first first stop element 261 rotates with the first planet gear 161 about the relevant planet gear rotational axis 46. A second 262 of the at least one first stop element is connected to, or forms part of, a second planet gear 162 of the at least one planet gear. The second first stop element 262 rotates with the second planet gear 162 about the relevant planet gear rotational axis 46.

[0079] Again, the at least one second stop element comprises two second stop elements 281, 282. A first 281 of the at least one second stop element is fixedly arranged in the module and in relation to the ring gear 12. A second 282 of the at least one second stop element is fixedly arranged in the module and in relation to the ring gear 12. The first and second, second stop elements 281 , 282 are arranged opposite to each other along the ring gear 12.

[0080] In Fig. 3a, the planet gear carrier 18 is prevented from rotation in a clockwise direction (in the view represented by Figs. 3a - 3d) by the first first stop element 261 being in contact with the first second stop element 281 and the second first stop element 262 being in contact with the second second stop element 282. Accordingly, the input shaft and the steering wheel of the vehicle are prevented from rotating further in this direction.

[0081] In Fig. 3b, a rotation of the steering wheel and the input shaft in an opposite direction has been initiated i.e, a counterclockwise rotation of the planet gear carrier 18 has been initiated, as indicated by the broad arrow. The first and second planet gears 161 , 162 rotate along the ring gear 12.

[0082] In Fig. 3c, the counterclockwise rotation of the steering wheel, the input shaft, and the planet gear carrier 18 has continued. The planet gear carrier 18 has rotated to a position wherein the first planet gear 161 is at the second second stop element 282 and the second planet gear 162 is at the first second stop element 281. The respective first stop elements 261 , 262 clear the respective second stop elements 281, 282.

[0083] In Fig. 3d, the counterclockwise rotation of the steering wheel, the input shaft, and the planet gear carrier 18 has continued until the first first stop element 261 is in contact with the first second stop element 281 and the second first stop element 262 is in contact with the second second stop element 282. Thus, the planet gear carrier 18, the input shaft, and the steering wheel are prevented from rotating further in the counterclockwise direction.

[0084] Fig. 4 schematically discloses details of a limiting mechanism 24. The limiting mechanism 24 is of the kind discussed herein.

[0085] In Fig. 4, for illustrating purposes only one planet gear 16, the ring gear 12, and the planet gear carrier 18 of the planetary gearset 10 are shown and one each of the first and second stop elements 16, 18 of the limiting mechanisms 24.

[0086] As mentioned above, each planet gear 16 is connected to the planet gear carrier 18 and is rotatable about a respective planet gear rotational axis 46. The planet gear rotational axis 46 is fixed in relation to the planet gear carrier 18. Accordingly, the planet gear rotational axis 46 travels along, or describes, a planet gear arc 50 as the planet gear carrier 18 rotates about the rotational axis 6.

[0087] Accordingly, the at least one planet gear 16 is configured to rotate about a planet gear rotational axis 46 on the planet gear carrier 18. The planet gear rotational axis 46 travels along a planet gear arc 50 as the planet gear carrier 18 rotates about the rotational axis 6 of the input shaft 4. The at least one second stop element 28 protrudes in a radial direction past the ring gear 12 towards the planet gear arc 50 and does so over a lesser distance d than up to the planet gear arc 50. The at least one first stop element 26 is arranged between a periphery p of the at least one planet gear 16 and the planet gear rotational axis 46. In this manner, conditions are provided for the planetary gearset 10 to be configured for the planet gear carrier 18 and the input shaft 4, and accordingly for the steering wheel of the vehicle, to rotate more than one full turn before the at least one first stop element 26 makes contact with the at least one second stop element 28.

[0088] Namely, in this manner, the planetary gearset 10 can be configured for the planet gear 16 to rotate along the ring gear 12 past the fixed second stop element 28 without the first stop element 26 of the planet gear 16 making contact with the second stop element 28. One such situation is shown in Fig. 3c. The position of the second stop elements 28 along the ring gear 12 obviously have to be chosen accordingly. Also the number of cogs of the gears 12, 14, 16 influence the rotational position of the first stop element 26 as the planet gear 16 approaches and passed the second stop element 28.

[0089] This arrangement of the at least one second stop element 28 and the at least one first stop element 26 provides for more than a 360 degrees rotation of the input shaft 4 and the steering wheel of the vehicle, see also the examples described further below.

[0090] The lesser distance d than up to the planet gear arc 50 of the second stop element 28 in a radial direction past the ring gear 12 is indicated in Fig. 4.

[0091] The radial direction is seen relative to the rotational axis 6.

[0092] It may be noted that the closer the at least one first stop element 26 is arranged to the planet gear rotational axis 46, the lesser a force the cogs of the at least one planet gear 16 are subjected to in the stop positions. Fig. 5 schematically shows a limiting mechanism 24 of a planetary gearset 10 according to an alternative example.

[0093] The limiting mechanism 24 of the Fig. 5 example resembles in much the previously discussed examples of the limiting mechanism 24. Accordingly, reference is also made to the above discussion. In the following mainly, the differences between the examples will be discussed.

[0094] Again, the limiting mechanism 24 comprises at least one first stop element connected to, or forming part of, the at least one planet gear and at least one second stop element fixedly arranged in the module 2. Again, there are two first stop elements 261 , 262. A first first stop element 261 at the first planet gear 161 and a second first stop element 262 at the second planet gear 162.

[0095] In the example of Fig. 5, the at least one second stop element comprises four second stop elements 281 , 282, 283, 284, and at least two of the four second stop elements 281 , 282, 283, 284 are arranged at least 100 degrees apart along the ring gear 12. In this manner, stopping angles of the steering wheel may be optimised for the steering system for different types of vehicles.

[0096] The rotation of the planetary gearset 10 is stopped when the two first stop elements 261, 262 make contact with two of the four second stop elements 281 , 282, 283, 284, preventing the steering wheel from turning too far and ensuring that the rotary connector assembly 34 is not rotated too much.

[0097] By positioning the four second stop elements 281, 282, 283, 284 in relevant positions along the ring gear 12, in particular, lesser rotational angles of the input shaft 4 and the steering wheel may be achieved than with only one or two second stop elements.

[0098] In Fig. 5, the second stop elements with reference numbers 281 and 284 are arranged at least 100 degrees apart. Also, the second stop elements with reference numbers 282 and 283 are arranged at least 100 degrees apart.

[0099] With reference to Figs. 3a - 5, the angle of rotation provided between the two end limits, or stop positions, of the module 2, as shown e.g., in Figs. 3a and 3d, depends on the size and number of cogs of the ring, sun, and planet gears 12, 14, 16 of the planetary gearset 10 as well as the size and number of the fixed at least one second stop element 28, 281, 282, 283, 284.

[0100] For instance, the at least one second stop element 28 may be wider than the at least one second stop elements 28, 281, 282 shown in Figs. 3a - 4, to provide earlier stop positions i.e. , a smaller rotational angle of the input shaft 4 and the steering wheel. A further option for adjusting the rotational angle of the input shaft 4 and the steering wheel may to arrange the four second stop elements 281, 282, 283, 284 shown in Fig. 5 at other circumferential distances from each other along the ring gear 12, than illustrated.

[0101] For instance, the sun gear 14 could be provided with 15 cogs, the at least one planet gear 16 could be provided with 140 cogs, and the ring gear 12 could be provided with 295 cogs. This configuration provides a gear ratio of 20,67 for the sun gear 14 to the planet gear carrier 18. A ratio of around 20 may be reasonable. It is easy to modify the ratio by changing the sized and number of cogs of the gears 12, 14, 16.

[0102] With the above ratio, in the example of Figs. 3a - 3d, the rotational angle between the two stop positions of the input shaft 4 may be approximately 1055 degrees or 2.9 steering wheel turns. This means that when rotating in one direction from a first stop position, the first stop elements 26 clear the fixed second stop elements 28 five times before again making contact with the second stop elements 28 again. Approximately this number of steering wheel turns may be suitable for a truck.

[0103] An exemplary rotary connector assembly 34 may provide for more than 3 full rotations without being damaged. Accordingly, the above example providing 2.9 steering wheel turns between the stop positions is suitable for such a rotary connector assembly 34.

[0104] By modifying the shapes of the at least one first and second stop elements 26, 28, other rotational angles can be achieved between the two stop positions, e.g., a rotational angle of about 885 degrees, corresponding to about 2.5 steering wheel turns may be achieved by broadening the second stop elements 28 in a circumferential direction of the ring gear 12 approximately two to three times a width of the second stop elements 281 , 282 indicated in Fig. 3a - 3d.

[0105] In the example of Fig. 5, the rotational angle between the two stop positions of the input shaft 4 may be approximately 730 degrees or about 2.0 steering wheel turns. This may be suitable for a passenger car. Fig. 6 schematically illustrates an example of a vehicle 40 comprising a steer-by-wire steering system 52.

[0106] The vehicle 40 may be any kind of vehicle configured for land-based propulsion and comprising a steering wheel, such as e.g., a buss, a truck, a heavy truck, a construction vehicle, or a car. In Fig. 6, the vehicle 2 is illustrated as a heavy load vehicle in the form of a truck.

[0107] The steer-by-wire steering system 52 is a system in the vehicle 40 that provides the functionality and control for the steering system. The steer-by-wire steering system 52 includes the module 2, which comprises the input shaft 4, the reduction gear 8, the electric motor 20, and the torque and angle sensor 32, as discussed above. These components work together to transmit the input motion from a steering wheel 42 of the vehicle 40 to steered wheels 44 of the vehicle 40, allowing the vehicle 40 to be steered in desired directions. Since the module 2 also may include a limiting mechanism 24 the steering wheel 42 may be prevented from turning too far, ensuring that the rotary connector assembly 34 is not rotated too much.

[0108] Accordingly, the vehicle 40 is equipped with the module 2 discussed herein, as part of its steer-by-wire steering system 52. Since the module 2 is designed to be compact, it is easy to fit into the vehicle 40.

[0109] The steering wheel 42 is connected to module 2, such as via the steering wheel shaft 36 or directly to the input shaft 4, see Fig. 1. This connection allows for the rotation of the steering wheel 42 and the transmission of the input motion from a driver of the vehicle 40 to the steer- by-wire steering system 52 of the vehicle 40.

[0110] The steered wheels 44 are controlled by the steer-by-wire steering system 52. The steered wheels 44 respond to the input motion transmitted from the steering wheel 42 through the module 2, allowing the vehicle 40 to be steered in desired directions. As discussed above, the torque and angle sensor 32 provides corresponding control signals.

[0111] Moreover, feedback is provided via the module 2 to the steering wheel 42 and the driver of the vehicle 40. The electric motor 20 of the module 2 is controlled to provide such feedback related to driving situations of the vehicle 40. The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0112] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0113] It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0114] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0115] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the invention, as defined by the appended claims.

Claims

CLAIMS1. A module (2) for a steer-by-wire steering system (52), the module (2) comprising an input shaft (4) configured to rotate about a rotational axis (6), a reduction gear (8), and an electric motor (20), wherein the reduction gear (8) comprises a planetary gearset (10) including a ring gear (12), a sun gear (14), and at least one planet gear (16) mounted on a planet gear carrier (18), wherein a motor shaft (22) of the electric motor (20) and the sun gear (14) are arranged concentrically with the rotational axis (6) of the input shaft (4), wherein the input shaft (4) is connected to the planet gear carrier (18), and wherein the motor shaft (22) of the electric motor (20) is connected to the sun gear (14).

2. The module (2) according to claim 1 , comprising a limiting mechanism (24) configured for limiting a rotation of the input shaft (4), wherein the limiting mechanism (24) is arranged at the planetary gearset (10).

3. The module (2) according to claim 2, wherein the limiting mechanism (24) comprises at least one first stop element (26) connected to, or forming part of, the at least one planet gear (16) and at least one second stop element (28) fixedly arranged in the module (2), and wherein a rotation of the planetary gearset (10) is stopped when the at least one first stop element (26) makes contact with the at least one second stop element (28).

4. The module (2) according to claim 3, wherein the at least one second stop element (28) is connected to, or forms part of, a flange (38) of the electric motor (20).

5. The module (2) according to claims 3 or 4, wherein the at least one second stop element (28) comprises two second stop elements (281 , 282), each of the second stop elements (281 , 282) being arranged at a distance from each other along the ring gear (12).

6. The module (2) according to any one of claims 3 - 5, wherein the at least one planet gear (16) comprises a first planet gear (161) and a second planet gear (162), wherein the at least one first stop element (26) comprises one stop element (261 , 262) arranged on each of the first and second planet gears (161 , 162).

7. The module (2) according to claim any one of claims 3 - 6, wherein the at least one second stop element (28) comprises four second stop elements (281 , 282, 283, 284), andwherein at least two of the four second stop elements (281, 282, 283, 284) are arranged at least 100 degrees apart along the ring gear (12).

8. The module (2) according to any one of claims 3 - 7, wherein the at least one planet gear (16) is configured to rotate about a planet gear rotational axis (46) on the planet gear carrier (18), wherein the planet gear rotational axis (46) travels along a planet gear arc (50) as the planet gear carrier (18) rotates about the rotational axis (6) of the input shaft (4), wherein the at least one second stop element (28) protrudes in a radial direction past the ring gear (12) towards the planet gear arc (50) and does so over a lesser distance (d) than up to the planet gear arc (50), and wherein the at least one first stop element (26) is arranged between a periphery (p) of the at least one planet gear (16) and the planet gear rotational axis (46).

9. The module (2) according to any one of the preceding claims, comprising a housing (30), wherein the ring gear (12) is fixed in relation to the housing (30).

10. The module (2) according to claim 9 and any one of claims 3 - 8, wherein the at least one second stop element (28) is directly or indirectly connected to the housing (30).

11. The module (2) according to any one of the preceding claims, comprising a rotary connector assembly (34) for electrical wiring, the rotary connector assembly (34) being connected to the input shaft (4).

12. A steer-by-wire steering system (52) for a vehicle (40), the steer-by-wire steering system (52) comprising a module (2) according to anyone of the preceding claims.

13. A vehicle (40) comprising a steer-by-wire steering system (52) according to claim 12.

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