Operating unit for a motor vehicle steer-by-wire system

Abstract

The present application relates to a kind of operating units for motor vehicle steer-by-wire system, it can be connected with steering device, so that the steering action of steering device is converted into the signal representing the steering action, and is transmitted to wheel executor, to realize the execution of steering action by the wheel of motor vehicle, wherein operating unit has telescopic slide-out mechanism, including telescopic carrier and telescopic slider linearly movable relative to telescopic carrier, wherein steering shaft is rotatably mounted in and / or on telescopic slider, and in telescopic slider is provided with corner limiter and with electrically energizable power feedback executor with electrically energizable motor and electrically energizable brake, wherein brake is designed as magneto-rheological brake, its maximum heating power is at most 1 / 5 of the maximum heating power of motor, and motor is arranged in the area of telescopic slider away from the end of steering device.

Description

Technical Field

[0001] This invention relates to an operating unit for a motor vehicle steer-by-wire system, which can be connected to a control device such that the steering action of the control device is converted into a signal representing the steering action and transmitted to the wheel actuators to execute the steering action through the wheels of the motor vehicle. The operating unit has a telescopic sliding mechanism, including a telescopic support member and a telescopic slider that is linearly movable relative to the telescopic support member. The steering shaft is rotatably mounted in and / or on the telescopic slider, and an angle limiter and a power-operated electric feedback actuator with an energized motor and an energized brake are provided in the telescopic slider. Background Technology

[0002] In today's automotive industry, the continuous development of new technologies is crucial for improving vehicle performance, safety, and driving comfort. One area receiving significant attention is steering technology, particularly "steer-by-wire" systems. These systems, which replace the mechanical steering column with an electrical signal system, offer numerous advantages over traditional steering systems. They enable flexible design, lighter vehicle weight, and superior driving dynamics. Steer-by-wire systems in motor vehicles eliminate the mechanical connection between the steering wheel and the wheels, transmitting the driver's steering actions through electronic control units and actuators. The core advantage of this technology lies in its ability to dynamically adjust steering characteristics, thereby optimizing driving stability and handling at different speeds and road conditions. Furthermore, the absence of a mechanical connection provides more space for innovative vehicle design and expanded safety features. Manufacturers can therefore place the steering wheel anywhere in the interior and even develop entirely new vehicle concepts without a traditional steering wheel. These systems not only enhance comfort and the driving experience but also facilitate the integration of autonomous driving functions. Improvements in feedback mechanisms and control algorithms ensure that the driver always maintains control of the vehicle, while laying the foundation for the future development of automated driving. Therefore, steer-by-wire systems represent a significant advancement in vehicle steering technology and have the potential to fundamentally change how vehicles are designed and operated.

[0003] The operating units of steer-by-wire systems are well known in the prior art. They are used to acquire the driver's steering actions, convert them into electronic control signals, and transmit them to the wheel actuators, which then transmit the steering actions to the vehicle's wheels. Typically, such operating units include force feedback actuators that provide the driver with tactile feedback about the road surface, as well as other mechanical and electronic components such as steering shafts, bearings, and steering angle sensors.

[0004] However, existing technologies have several drawbacks, particularly regarding the thermal characteristics of these actuators. Integrating force feedback actuators, consisting of an electric motor and a brake, often results in significant heat generation. This heat can not only affect the function of the force feedback system but also cause adjacent components, such as the steering shaft, bearings, or actuator housing, to overload due to thermal stress. Heat dissipation is a significant challenge, especially in the compact structures required by modern vehicles. Typically, the generated heat cannot be efficiently dissipated, leading to component overheating and impacting the lifespan and reliability of the actuator. Summary of the Invention

[0005] The objective of this invention is to avoid or at least reduce the problems known in the prior art and to provide a thermally optimized operating unit for a vehicle steer-by-wire system.

[0006] This invention solves the above-mentioned tasks through an operating unit for a vehicle steer-by-wire system. The operating unit can be connected to a control device, so that the steering action of the control device is converted into a signal representing the steering action and transmitted to the wheel actuator to realize the steering action through the wheels of the vehicle. The operating unit has a telescopic sliding mechanism, including a telescopic support member and a telescopic slider that can move linearly relative to the telescopic support member. The steering shaft is rotatably mounted in and / or on the telescopic slider. An angle limiter and a power-feedback actuator with an energized motor and an energized brake are provided in the telescopic slider. The brake is designed as a magnetorheological brake, whose maximum heat output is at most 1 / 5 of the maximum heat output of the motor. The motor is located in the far end region of the telescopic slider away from the control device.

[0007] Positioning the motor at the farthest end of the telescopic slider ensures its distance from the control device. This reduces direct heat transfer to the control device and adjacent components, minimizing the overall thermal load on the operating unit. Simultaneously, the telescopic slider provides a large heat dissipation surface between the motor and the control device. For thermal management, the magnetorheological brake's maximum heat dissipation power is only 1 / 5 that of the motor. This allows the brake to be positioned closer to the control device than the motor. This specific limitation on heat dissipation power ensures sufficiently high torque can be provided during continuous operation of the operating unit without the risk of thermal overload. This not only improves functional safety but also ensures the durability and reliability of the operating unit in harsh applications.

[0008] Placing the motor at the farthest end of the telescopic slider also ensures that the main heat source is kept away from areas where hands might come into contact with the telescopic slider or steering wheel. This structure provides excellent thermal insulation against hand contact because heat transfer from the motor to the surface of the telescopic slider is minimized, preventing the surface from reaching temperatures that could be dangerous or detrimental to the driver. This is particularly advantageous during extended operation of the control unit, as the telescopic slider itself does not heat up significantly, thus ensuring a high level of operational comfort.

[0009] Optimized thermal management in the operating unit not only contributes to functional safety but also improves energy efficiency by eliminating the need for additional, especially active, cooling systems. This offers an economic advantage in space-constrained and thermally demanding applications.

[0010] Therefore, the operating unit preferably does not include an active cooling system, such as fluid cooling or a fan.

[0011] First, we will discuss the various components or parts of the steer-by-wire system, and then list particularly preferred embodiments.

[0012] steer-by-wire system In this patent application, steer-by-wire system refers to a steering system for a motor vehicle that eliminates the mechanical connection between the operating unit and the steering mechanism used to adjust the vehicle wheels. Instead, it transmits steering actions and commands electronically, achieving precise and flexible control of the vehicle. Steer-by-wire systems offer significant advantages over traditional steering systems in terms of weight savings, design freedom, and driving comfort. In particular, eliminating the steering column and mechanical components reduces vehicle weight and complexity, while allowing for more flexible interior layout.

[0013] The functions of a steer-by-wire system include, for example, converting steering wheel movements into electronic signals and sending them to a control unit. This control unit analyzes the input and controls the steering actuators of one or more wheels to bring the wheels to the desired steering angle. This enhances adaptability to different driving situations and facilitates the integration of additional functions such as lane-keeping assist or autonomous driving.

[0014] motor vehicles In this patent application, a motor vehicle refers to a motorized land vehicle used for transporting people or goods, particularly suitable for use on roads. It includes all vehicles powered by an engine, including but not limited to automobiles, trucks, buses, and motorcycles. Motor vehicles may employ different drive systems, such as internal combustion engines, electric motors, or hybrid power systems.

[0015] Front axle steering In this application, front axle steering refers to a component of a motor vehicle used to control the direction of the front wheels in order to steer the vehicle according to the requirements of the driver and / or control program.

[0016] Operation unit In this patent application, the operating unit refers to a device used by a user to control the direction of travel of a motor vehicle, particularly for use in a steer-by-wire system. This operating unit converts the driver's steering actions into electronic signals to adjust the actual steering action of the vehicle's wheels. The core task of the operating unit is to provide the driver with a steering feel as close as possible to that of a mechanical steering system, achieving intuitive and safe vehicle control. To this end, the operating unit can provide variable resistance torque on the steering shaft, thereby generating tactile feedback, and can be adjusted according to the driving situation.

[0017] Force feedback actuator In this invention, a force feedback actuator is a device for transmitting tactile and / or force feedback to the driver by applying force to a control mechanism in contact with the driver. This feedback simulates the steering force transmission feel in a conventional mechanical or hydraulic steering system. The force feedback actuator generates force via electronic control commands, reflecting the current driving state and road conditions, providing the driver with a realistic steering feel. The force feedback actuator can employ an electric motor, brake, magnetic coil, or other suitable components to generate the required force.

[0018] Force feedback actuators can operate actively (e.g., electrically) or passively (e.g., through generators). In active mode, the actuator is driven by an external energy source, such as an electric motor, to apply force to the control device to generate tactile feedback. This means the actuator is controlled to provide perceptible feedback to the user, such as simulating real forces in a vehicle's steering input. In passive mode, the actuator operates as a generator, converting and utilizing or consuming the kinetic energy generated by the control device or other user interactions. In this mode, external drive is not necessarily required; instead, the mechanical energy input from the control device is used to generate resistance or damping. This mode is particularly useful for improving efficiency and energy saving because it utilizes regenerative forces and provides additional realistic tactile feedback. By being able to switch between active and passive modes, force feedback actuators can flexibly and efficiently meet different tactile feedback needs and can dynamically switch according to requirements, load conditions, or applications.

[0019] Preferably, the force feedback actuator includes an electric motor, particularly a gearless electric motor.

[0020] In addition, the force feedback actuator may include a brake.

[0021] Particularly preferably, the force feedback actuator includes an electric motor and a brake, especially preferably an energized brake.

[0022] electric motor In this patent application, the electric motor is a motor device that, in conjunction with a force feedback actuator, is used within the operating unit of a steering-by-wire system to apply torque to the steering shaft in a targeted manner, providing the driver with tactile feedback regarding driving status or specific steering resistance. The electric motor can be actively controlled to generate specific resistance or auxiliary torque based on driving parameters, road conditions, or driver assistance systems, thereby creating a controlled steering feel.

[0023] The electric motor consists of a stator and a rotor assembly. The rotor is preferably connected to the steering shaft directly or via gears, thereby transmitting torque to the steering shaft through targeted current control. The electric motor can be designed as a radial flux motor or an axial flux motor.

[0024] The electric motor can be geared or operate gearless. Geared connection allows for adjustment of torque and speed according to the specific needs of the operating unit. Preferably, planetary gears or harmonic gears can be used to achieve efficient and low-backlash precise torque transmission. Geared connection is particularly advantageous when using a small, high-speed electric motor and needing to convert torque to a suitable magnitude for the force feedback system. Alternatively, the electric motor can operate gearless when direct torque transmission to the steering shaft is required.

[0025] brake In this patent application, a brake is a device within the operating unit of a steer-by-wire system for applying controlled power to the steering shaft in a targeted manner to influence, limit, or dampen its movement. The brake can be used in particular to provide specific resistance to the rotational movement of the steering shaft to create a realistic steering feel, or to achieve safety restrictions on steering actions.

[0026] The brake can preferably be an electromagnetic or electromechanical structure, so that its braking force can be actively adjusted by a control unit. In a preferred embodiment, the brake includes an energized braking component that applies a friction-, magnetic, or fluid-based braking force to a component connected to the steering shaft. The braking force can be dynamically adjusted according to different operating parameters, such as vehicle speed, steering angle, or driving conditions.

[0027] Particularly preferably, the brake can be a magnetorheological brake.

[0028] The brake can also be a mechanical friction brake, wherein brake pads press against a braking surface connected to the steering shaft, thereby achieving a torque-related steering shaft delay. In another preferred embodiment, the brake can also be an eddy current brake, which generates a magnetic field and induces braking force on a conductive disc, achieving a wear-free and virtually noiseless braking effect. Alternatively, the brake can also be an electromechanical clamping device, which uses electrically or magnetically driven clamping elements to specifically suppress or completely prevent rotation of the steering shaft.

[0029] Preferably, gears (such as planetary gears) can also serve as brakes in the sense of this patent application. Due to their internal friction, gears can brake the steering shaft, suppressing or slowing rotational motion. In particular, gear configurations with specific transmission ratios and frictional characteristics can be used to provide a certain basic frictional torque without the need for additional active braking components, or to assist active braking components. Such gears can be integrated into the entire system for damping steering action or providing specific drag curves to simulate conventional mechanical steering.

[0030] Preferably, the brake is integrated within the telescopic slider, achieving a compact structure and optimized mass distribution. The brake can be positioned between the angle limiter and the electric motor, thus working synergistically throughout the steering resistance and feedback system. The brake can be designed to continuously provide adjustable braking force or to actively engage under specific operating conditions, such as to limit the maximum steering angle or generate specific tactile feedback. In a particularly preferred embodiment, the brake can be coupled to the electric motor, with both working together to achieve fine-tuning of the steering feel.

[0031] Magnetorheological braking device In this patent application, a magnetorheological braking device is a device that utilizes a magnetorheological medium to generate a variable controllable braking torque between a rotor and a stator. The magnetorheological medium is preferably a liquid or gaseous carrier fluid containing dispersed magnetic particles. When a magnetic field is applied, these particles align along the magnetic field lines, causing an increase in the medium's viscosity and a significant increase in its shear strength. By adjusting the magnetic field strength, the braking force can be specifically controlled. The magnetorheological braking device is preferably designed with a rotatable shaft passing through the rotor, and the rotor coaxially arranged on the shaft. The rotor is preferably made of a metal plate. The rotor and stator are preferably encapsulated together in a housing, which forms a space for accommodating the magnetorheological medium. The stator is equipped with magnetic coils that generate a magnetic field when energized, affecting the magnetorheological medium within the accommodating space. The magnetic field is controlled to generate a variable braking force between the rotor and stator, increasing the shear strength of the medium by activating the magnetic field. Preferably, the magnetorheological braking device is equipped with seals to prevent leakage of the medium from the braking housing and to protect the internal components of the brake from contamination.

[0032] Multiple magnetorheological braking devices can also be advantageously employed to achieve a higher total braking torque. This configuration also allows braking force to be distributed to multiple axes or components of the operating unit, improving the system's flexibility and adaptability. By using multiple braking devices simultaneously, the braking effect can be controlled more precisely because each unit can be controlled independently. This is particularly advantageous in complex systems or applications requiring different braking torques at different locations. Furthermore, the redundancy of multiple braking devices enhances operational safety, ensuring that even if one unit fails, the others can continue to operate normally.

[0033] Dividing the brake into multiple independent braking units also reduces the inductance of each braking segment. Lower inductance means a shorter coil response time, allowing current changes to occur more quickly, thus optimizing the brake's dynamic response. A faster dynamic response means the brake can respond more quickly to changing operating conditions, which is particularly advantageous in applications with rapidly changing load demands.

[0034] It is also conceivable that a magnetorheological brake has two spatially separated excitation coils. This configuration allows for more targeted and flexible control of the magnetic field, generating different magnetic field strengths in different regions of the magnetorheological medium. The spatial separation of the excitation coils can generate independent magnetic fields acting on specific particle concentrations or movements within the medium. This benefits by allowing for individual adjustment of the braking force according to the needs of different operating conditions. Furthermore, this arrangement can result in more uniform heat distribution, improving the thermal stability of the braking device. Similarly, redundancy can be achieved through the second excitation coil, ensuring that even if one excitation coil fails, the other remains functional.

[0035] The excitation coils can preferably be connected in parallel. The parallel use of coils in magnetorheological braking devices offers significant advantages, particularly in terms of dynamic response and compensation capabilities. By connecting inductors in parallel, the total magnetic field capacity increases. This results in a faster system response because the magnetorheological medium responds more quickly to changes in the magnetic field. The dynamic response of the brake is thus improved, allowing for more precise and immediate adjustment of the braking force to adapt to changing operating conditions. Another advantage of parallel connection is enhanced system compensation capability. If one coil in the parallel connection fails or malfunctions, the remaining coils can still effectively generate the required magnetic field. This improves the reliability and fault tolerance of the braking device.

[0036] Brake rotor In this patent application, the brake rotor of the magnetorheological brake is a rotating element directly connected to the rotor shaft, serving as the active braking component in the system. The brake rotor interacts directly with the magnetorheological medium, which is arranged between the rotor and the brake stator. The function of the brake rotor is to convert the viscosity change of the magnetorheological medium into the required braking torque through its rotation in the magnetic field. This allows for the adjustment and control of the braking torque acting on the shaft, achieving precise braking adjustment of the entire steering system. Preferably, the brake rotor can be a metal plate structure.

[0037] Brake stator In this patent application, the brake stator is a component fixedly mounted relative to the brake housing in a magnetorheological brake, constituting the stationary part of the brake, and is preferably designed as a cylindrical sleeve. The function of the brake stator is to house the brake rotor and, together with the brake housing, form a magnetorheological medium cavity, in which the medium is located. Preferably, the brake stator is designed to have an inner surface along which the rotor can move with a specific working gap. The function of the brake stator is to absorb the braking torque transmitted by the brake rotor through the medium, thereby ensuring reliable force transmission in the steering system.

[0038] The stator of the magnetorheological braking device is preferably a multi-component structure, including a coil support, a closed loop, and an outer tube. These components are preferably manufactured from sheet metal using a forming process. Preferably, these components are interconnected via a forming connection, thereby creating a large-area, compact contact between the stator components. This reduces the magnetic reluctance within the assembly, significantly improving the efficiency of the magnetic circuit. The reduced magnetic reluctance helps achieve higher braking torque without increasing the coil current. This improves the energy efficiency of the braking device and allows for a more compact and cost-effective design of the electrical components.

[0039] magnetic field generator In this patent application, a magnetic field generator is a device used to generate or regulate an electromagnetic field within a magnetorheological brake to selectively control the flow characteristics of the magnetorheological medium. The generated magnetic field penetrates the medium cavity formed by the brake rotor and brake stator, causing changes in the rheological properties of the medium, thereby increasing its shear viscosity and establishing a corresponding braking torque. Preferably, the magnetic field generator can be designed as an energized electromagnet with its coil wound on a ferromagnetic core, and the magnetic lines of force are selectively guided to the working area through appropriate shaping. Its advantage lies in its ability to steplessly adjust the braking torque according to the applied current, thereby achieving precise and rapid adaptation to different driving situations in the steer-by-wire system. Preferably, the magnetic field generator is integrated into the brake housing or brake stator region to achieve a shorter magnetic flux path and efficient magnetic field-medium coupling. Alternatively, a permanent magnetic field source can be used to replace or supplement the electromagnet for use when a basic magnetic field is required or for fault protection.

[0040] To produce a braking effect, the magnetic field generator can be designed to be controllable, enabling it to generate a magnetic field with a predetermined field strength and / or predetermined flux when controlled. Specifically, the magnetic field generator can be configured to adjust the field strength and / or flux between zero and a predetermined maximum value. In this way, the resulting initial braking effect can also be controlled or adjusted. For this purpose, the magnetic field generator can be designed as a coil whose magnetic field depends on the current flowing through the coil windings. By adjusting the current intensity, the field strength and / or flux can be adjusted between zero and a predetermined maximum field strength and / or maximum flux, thereby regulating the braking effect. Preferably, the magnetic field generator is housed within the stator of the magnetorheological brake.

[0041] magnetorheological media In this patent application, the magnetorheological medium is a substance whose rheological properties, particularly viscosity and flowability, change according to an applied magnetic field. It comprises, for example, a liquid or gaseous carrier fluid in which magnetic particles are finely dispersed. These particles are preferably spherical or near-spherical and have a permeability responsive to the magnetic field. The carrier fluid is preferably oil or other suitable liquid medium, or a gas such as air, ensuring uniform suspension and easy movement of the particles in the absence of a magnetic field. In this invention, the magnetorheological medium functions to achieve adjustable mechanical energy transfer. When a magnetic field is applied, the magnetic particles align along magnetic lines of force, forming a chain-like structure. This structure significantly increases the flow resistance of the medium and allows for targeted control of torque transmission between the rotor and stator. The intensity of this torque transmission can be adjusted by the intensity of the applied magnetic field, thereby achieving precise and dynamic adjustment of braking characteristics.

[0042] The preferred particle concentration in the carrier fluid is 20 to 50 volume percent. A concentration of approximately 30 to 40 volume percent is particularly advantageous because it achieves an optimal balance between maximizing the magnetorheological effect and minimizing viscosity in the absence of a magnetic field. This concentration allows for precise control of rheological properties while ensuring good pumpability and operability of the medium within the system.

[0043] magnetorheological particles In this patent application, magnetorheological particles refer to magnetizable or responsive particles suspended in a carrier fluid, which selectively alter the fluid's flow characteristics through the action of a magnetic field. Preferably, these particles are made of iron or iron alloys and possess high magnetic permeability, enabling them to form chain-like structures in a very short time when a magnetic field is applied, thereby increasing the viscosity or flow resistance of the magnetorheological medium. These particles thus allow for rapid and controllable enhancement of the shear force between the rotor and stator, facilitating the adjustment of braking effects. Their ability to rapidly and reversibly adjust the direction of the magnetic field makes the adjustment of braking characteristics extremely precise and dynamic, with the shear strength of the medium being affected almost without delay.

[0044] The particles are preferably coated to reduce agglomeration and sedimentation, thus maintaining a uniform distribution in the carrier medium even during long-term operation. The carrier liquid is preferably made of materials with high thermal stability and low aging properties to ensure the performance of the medium under different thermal and mechanical conditions. The magnetic particles are preferably made of ferromagnetic or superparamagnetic materials. Suitable materials include iron, nickel, cobalt and their alloys, or ferrite compounds such as iron oxide (Fe3O4). These materials have high magnetic permeability and saturation magnetization, enabling them to respond efficiently to applied magnetic fields.

[0045] The particle size is preferably between 0.1 micrometers and 10 micrometers, with 1 micrometer to 5 micrometers being particularly desirable. This particle size distribution ensures stable suspension of the particles in the carrier liquid, reduces sedimentation, and ensures that the particles can form structures quickly and efficiently when a magnetic field is applied.

[0046] Brake housing In this patent application, the brake housing of the magnetorheological brake is a component of the external enclosure structure of the brake, surrounding and forming a space for accommodating the magnetorheological medium (magnetorheological medium cavity). The main function of the brake housing is to safely contain the magnetorheological medium and allow the medium to interact between the brake rotor and the brake stator. As a "frame structure," the brake housing not only protects the internal components from external influences but also serves as a basis for the proper alignment of all internal parts.

[0047] The brake housing can be made of a variety of materials, with metal alloys, plastics or composite materials being preferred.

[0048] Brake housings can be either one-piece or multi-piece structures. One-piece housings offer high structural integrity and reduce potential weaknesses arising from connections. Multi-piece housings, on the other hand, support a more modular structure, facilitating maintenance and replacement of individual components.

[0049] In principle, it is also conceivable that the stator may be at least partially or wholly used as a brake housing or a part thereof.

[0050] Steering shaft In this patent application, the steering shaft is a mechanical component that serves as a rotating shaft within the operating unit for transmitting torque and / or rotational motion. The steering shaft is designed to rotate about a specific axis and is mechanically connected to the operating unit's control mechanism (such as a steering wheel or joystick). Its primary function is to transmit the rotational motion generated by the control mechanism to subsequent mechanical or electronic components within the steer-by-wire system's operating unit.

[0051] The steering shaft can be a single piece or a multi-piece structure. A single-piece structure offers high structural integrity and extremely high torque transmission accuracy because there are no additional connection points. A multi-piece structure supports modular design, allowing different sections to be optimized for different needs. Multi-piece structures can also integrate joints or couplings to achieve flexible connections between sections and compensate for tolerances. This configuration also facilitates maintenance or replacement of individual sections and better adapts to complex space requirements.

[0052] Preferably, the steering shaft is mounted in a steering angle limiter, which mechanically restricts the rotational movement of the steering shaft.

[0053] The brake rotor is preferably fixedly connected to the steering shaft.

[0054] Telescopic sliding mechanism In this patent application, the telescopic sliding mechanism is a mechanical unit comprising a telescopic support member and at least one telescopic slider that is linearly movable relative to it. The telescopic sliding mechanism enables controlled linear movement between these two components, with the telescopic slider guided within a predetermined range along the extension direction. Guiding is preferably achieved via at least two linear bearings, ensuring both precise motion guidance and the mechanical stability of the entire system.

[0055] The telescopic slider can integrate multiple operating units. Preferably, it includes a force feedback actuator with a motor and magnetorheological brake, as well as an angle limiter. This compact integration achieves a space-saving structure for the operating units.

[0056] The telescopic sliding mechanism is also designed to ensure reliable thermal isolation between its components, particularly by selecting materials with specific thermal conductivity and optimizing the arrangement of heat-generating parts.

[0057] linear bearings In this patent application, the linear bearing is a mechanical device that enables precise, low-friction guidance and movement of a telescopic slider relative to a telescopic support member along a linear axis.

[0058] Linear bearings can be either linear rolling bearings or linear sliding bearings. Linear rolling bearings use rotating or spherical elements, such as balls or rollers, arranged between guide members and bearing components. These rolling elements roll between contact surfaces, minimizing friction. These bearings typically include rolling element guides, cages for positioning the rolling elements, and seals to prevent contamination. Linear sliding bearings, on the other hand, do not contain rolling elements; the contact surfaces of their bearing components slide directly on the guide members, often using friction-reducing materials such as polytetrafluoroethylene (PTFE) or coated metal. Due to direct sliding, sliding bearings dissipate heat more easily and have a simpler mechanical structure.

[0059] Preferably, linear bearings also contribute to the thermal isolation of the system through their thermal conductivity characteristics, and can be adjusted according to the overall system requirements.

[0060] Telescopic slider In this patent application, the telescopic slider is a component of the telescopic sliding mechanism, capable of linear movement relative to the telescopic support member. The telescopic slider is particularly used to achieve linear displacement of the operating device within the operating unit.

[0061] The telescopic slider is preferably made of material with a thermal conductivity greater than 40 W / m. K, preferably 30 to 50 W / m Material K is used to ensure controlled heat dissipation and minimize thermal stress. Aluminum or aluminum alloys are particularly preferred, with a thermal conductivity of up to 230 W / m*K. The outer surface of the telescopic slider is designed with a large surface area to facilitate heat dissipation and convection, thereby further reducing the thermal load on the unit.

[0062] The core components of the force feedback system are preferably arranged inside the telescopic slider, particularly the energized electric motor located at the end of the telescopic slider away from the operating device, and the magnetorheological brake for precise control of the return torque. This arrangement achieves a compact and space-saving structure and optimizes the location of the heat source, preventing overheating of the operating unit.

[0063] The telescopic slider is preferably a tubular structure, and more preferably has a polygonal cross-section. This polygonal cross-section effectively prevents the slider from rotating about its longitudinal axis, further improving guiding stability and positioning accuracy.

[0064] Expansion load-bearing components In this patent application, the telescopic carrier is a component of the operating unit, providing a basis for guiding the telescopic slider. As a fixed element relative to the vehicle, the telescopic carrier allows the telescopic slider to move linearly along a defined axis. It constitutes the mechanical interface between the movable slider and the rest of the steering system.

[0065] The telescopic carrier may also be provided with mounting points or connection interfaces for additional components (such as sensors or actuators) that are essential for the operation of the steering system. Furthermore, the telescopic carrier can be connected to the steering column adjustment device, specifically enabling tilt adjustment of the operating unit relative to the driver.

[0066] Corner limit switch In this patent application, the angle limiter is a device used to mechanically or functionally limit the maximum rotation angle of the steering shaft within an operating unit. The angle limiter ensures that the angle of rotation of the operating device does not exceed a predetermined limit to prevent damage to mechanical or electronic components, while ensuring precise control of steering actions.

[0067] The function of the angle limiter is particularly that when the preset maximum angle is reached, it physically prevents the steering shaft from continuing to rotate or gradually increases the reaction force.

[0068] Advantageous implementation methods According to an advantageous embodiment of the invention, the thermal conductivity of the telescopic slider can be set to be greater than 40 W / m*K. This thermal conductivity ensures that the generated heat can be dissipated efficiently without causing overheating of critical components (such as steering shafts, sensors, or bearings). Simultaneously, the thin wall thickness of the telescopic slider prevents excessively rapid heat loss, thereby reducing potential thermal stress and maintaining the long-term mechanical stability of the operating unit. These thermal properties are of great significance for the functional safety and durability of the system, especially in compact structures.

[0069] According to another preferred improvement of the present invention, the outer surface area of ​​the telescopic slider can also be set to 40,000-100,000 mm². 2 The preferred range is 50,000-87,000 mm. 2This measure significantly reduces the thermal load on internal components, which is particularly beneficial during high-intensity use of force feedback actuators. Optimized heat dissipation not only contributes to functional safety but also improves energy efficiency, as it eliminates the need for an additional cooling system. This offers an economic advantage in space-constrained applications with high thermal requirements.

[0070] Furthermore, according to another preferred embodiment of the invention, the average distance between the outer surface of the telescopic slider and the telescopic support member can be set to be less than 5 mm. This average distance of less than 5 mm between the outer surface of the telescopic slider and the telescopic support member achieves an extremely compact structure while improving thermal insulation between the slider and the support member. This allows heat to be directly transferred to the telescopic support member, thereby reducing the thermal load on the telescopic slider and adjacent components. This measure improves the heat dissipation efficiency of the slider and contributes to the durability of the system.

[0071] According to another particularly preferred embodiment of the invention, the magnetorheological brake can be positioned in front of the motor when viewed from the steering mechanism direction. By arranging the magnetorheological brake in front of the motor, the brake, as a component with low heat absorption capacity and low self-heating, is located in the motor's thermal path. The brake thereby reduces the thermal impact towards the steering wheel and, as a thermal mass buffer, reduces temperature variations in the motor. This also allows for more precise control feedback even during extended operation.

[0072] Furthermore, the invention can be further improved such that the telescopic slider is guided relative to the telescopic support member via a first linear bearing and a second linear bearing, and the thermal conductivity of the first linear bearing and / or the second linear bearing is less than that of the telescopic slider. This thermal isolation measure protects heat-sensitive components or touchable surfaces on the telescopic support member near the steering wheel area from overheating and achieves a more uniform heat distribution.

[0073] Preferably, the thermal conductivity of the first linear bearing and / or the second linear bearing is 0.1-1.0 W / m. K, preferably 0.2-0.5 W / m K.

[0074] In another preferred embodiment of the invention, the thermal conductivity of the telescopic support member can be set to be greater than that of the telescopic slider. Selecting a telescopic support member with a higher thermal conductivity than the telescopic slider allows excess heat to be directed to less sensitive areas of the operating unit or vehicle structure. This protects heat-sensitive components in the slider area while efficiently dissipating heat through the support member.

[0075] Against this backdrop, the thermal conductivity of the expansion joint is particularly preferred to be 51-230 W / m. K, preferably 80-230 W / m K.

[0076] The invention can be further improved such that the steering shaft is guided relative to the telescopic slider via a first steering shaft bearing and / or a second steering shaft bearing, and the thermal conductivity of the first steering shaft bearing and / or the second steering shaft bearing is lower than that of the telescopic slider. Using steering shaft bearings with lower thermal conductivity than the telescopic slider prevents unwanted heat transfer to the steering shaft. This measure reduces deformation due to thermal expansion, helping to ensure the accuracy and function of the steer-by-wire system over the long term.

[0077] Finally, the present invention can also advantageously set the total moving mass of the telescopic slider (including integrated components) to 2-10 kg, preferably 2-8 kg, and particularly preferably 3-6 kg. The mass within the telescopic slider increases the thermal inertia of the operating unit in that area, while maintaining the stability and functionality of the system.

[0078] Preferably, the maximum movement speed of the telescopic slider during extension and retraction is 20-60 mm / s. This speed range strikes a balance between the responsiveness and precision of the extension and retraction motion, which is particularly important in steer-by-wire systems. A maximum speed of 20 mm / s to 60 mm / s allows for rapid movement, which is especially advantageous in situations requiring quick reset or positioning, such as getting in and out of the vehicle. This speed range prevents components such as the electric adjustment actuator from operating under high loads for extended periods, thus extending the lifespan of mechanical and electrical components. Furthermore, a defined maximum speed range enhances interaction with automated or safety-critical functions, such as automatic steering wheel return to zero. Speed ​​control enables smooth, predictable movement, preventing unexpected or sudden reactions. This is crucial for system acceptance and driver trust in steer-by-wire technology.

[0079] Equally advantageous is the telescopic slider's length range of 200-350 mm. This length achieves an optimal balance between a compact structure and providing the necessary space for integrating all critical components, such as the steering shaft, magnetorheological brakes, electric motors, and guiding elements. This ensures the telescopic slider can accommodate all required functional units without unnecessarily increasing the overall size of the operating unit. This is particularly advantageous in vehicles with limited cockpit space. Furthermore, this length range allows for more precise linear guidance of the telescopic slider relative to the telescopic carrier. Sufficient length and bearing spacing ensure slider stability during guidance, enhancing mechanical strength and operational safety. This minimizes unwanted movement, vibration, or slider tilting, ensuring precise force transmission and thus improving driving safety and steering feel. Additionally, this length increases the flexibility of the operating unit design. For example, the electric motor and brakes can be strategically positioned to achieve optimal load distribution within the operating unit. This contributes to a balanced weight distribution, positively impacting the system's dynamic characteristics, such as inertial behavior and steering response.

[0080] Furthermore, the preferred length of the telescopic carrier is 110-350 mm. The main advantage of this size is improved mechanical stability of the telescopic carrier. This length ensures reliable guidance of the telescopic slider even under significant forces during operation. This minimizes vibration, torsion, or unwanted backlash in the system, thereby improving steering input accuracy. Additionally, this length range allows the operating unit to be adapted to different vehicle designs and space requirements. Flexible adjustment of the telescopic carrier length allows the operating unit to be integrated into both compact vehicles and larger cockpits without fundamental design changes. This improves adaptability and reduces development and manufacturing costs when integrating across different vehicle models. Another advantage is improved kinematics of the telescopic movement. This length range allows for precise guidance of the telescopic slider within a sufficiently large adjustment range. This helps optimize driver ergonomics, as the position of the control device better adapts to the driver's individual needs and preferences. The wider adjustment range also facilitates adaptation to drivers of different heights or seating positions.

[0081] According to a preferred improvement of the invention, the wall thickness of the telescopic slider along its length can also be set to 1.5-3.0 mm, achieving an optimal balance between stability, weight, and manufacturing cost, combining functional and economic advantages. From a technical perspective, this wall thickness range ensures that the telescopic slider can safely withstand the forces and torques generated during the operation of the operating unit without deformation or structural weakness. This is particularly important because the telescopic slider needs to accommodate and guide the steering shaft and force feedback components. The slider weight achieved with this wall thickness also contributes to improved system dynamic performance, as the slider can be driven with less energy. The 1.5-3.0 mm wall thickness also facilitates the use of non-cutting forming processes (such as deep drawing, bending, or thin-wall casting), eliminating the need for complex machining.

[0082] Furthermore, the cross-sectional area of ​​the telescopic slider along its length is preferably 2,700-5,200 mm². 2 This cross-sectional area range achieves mechanical stability and balanced acoustic characteristics for the telescopic slider (e.g., a higher natural frequency). The slider is robust enough to reliably withstand and transmit the forces and torques generated during operation of the operating unit (especially the force feedback system). Simultaneously, it minimizes unwanted deformation or bending, enabling precise and uniform force transmission, which is particularly important in dynamic steering maneuvers. The slider's mass is also sufficiently high to help absorb vibrations. Furthermore, this cross-sectional area range ensures low inertia for rapid and precise movement, while maintaining sufficient mass to suppress vibrations. This cross-sectional area also provides ample space for integrating necessary force feedback components such as motors, magnetorheological brakes, angle limiters, and steering shafts.

[0083] Another advantage is that the moment of inertia of the telescopic slider is 400-500 cm. 4This range of moment of inertia ensures sufficient rigidity for the telescopic slider, avoiding or reducing deformation caused by bending or torque, especially under dynamic loads such as rapid turns or sudden load changes. Furthermore, the optimized moment of inertia minimizes vibration and resonance effects in the system. This combination of rigidity and low deformation allows for more precise linear movement of the telescopic slider along the telescopic support. This is particularly important when using linear bearings, as they are more sensitive to slider deformation due to their constant guiding force.

[0084] Preferably, the steering shaft is fixed within the telescopic slider in the extension direction of the telescopic slider. By integrating the steering shaft into the telescopic slider, it is ensured that the movement of the steering shaft is completely synchronized with the movement of the slider. By coupling the steering shaft to the telescopic slider, the load generated during steering actions is specifically distributed to the slider. Integrating the steering shaft into the telescopic slider also means that there is no need to set additional guide elements or mounting points outside the slider, which is particularly advantageous in vehicles with limited space. Another advantage is improved vibration and noise suppression.

[0085] Furthermore, it is particularly preferable to arrange the brake, force feedback actuator, and angle limiter sequentially within the telescopic slider, such that, starting from the far end near the control device, the angle limiter, brake, and force feedback actuator are arranged in sequence, moving towards the far end of the slider away from the control device. Placing the angle limiter directly near the control device allows for precise mechanical restriction of the steering shaft directly connected to the control device. This effectively controls the maximum rotational movement of the control device without introducing mechanical backlash or delay through intermediate components. This direct arrangement achieves precise control and enhances the driver's feedback experience. The brake and force feedback actuator are relatively heavy components; by placing them far from the angle limiter and near the far end of the slider, the center of mass of the moving parts within the telescopic slider is optimized. In particular, placing the heavier brake and actuator at the far end also serves as a damping element for vibrations caused by the control device or external forces.

[0086] This arrangement also optimizes heat distribution within the telescopic slider. Because the force feedback actuator, as the primary heat source, is positioned at the far end, direct heat transfer to the corner limiter, brake, and steering wheel is minimized. This ensures the functionality of these components even under high thermal loads. Simultaneously, the brake, located between the corner limiter and the actuator, acts as a thermal buffer, reducing the thermal load on the steering wheel and its integrated sensitive components (such as buttons and airbags).

[0087] In another preferred improvement of the invention, the steering shaft can be configured to pass at least partially, preferably entirely, through the brake, force feedback actuator, and corner stop. The main advantage of this arrangement is that it allows for a compact, space-saving structure for the operating unit. Furthermore, the axial passage of the steering shaft ensures precise alignment of all mechanical and electromagnetic components. This axial alignment reduces potential misalignment or mechanical backlash caused by separate arrangements or more complex coupling mechanisms. This optimizes the accuracy of force transmission from the force feedback actuator to the steering shaft, improving steering precision and driver feedback. Another advantage is the reduction in the number of bearings or connecting elements required, which would be necessary if the steering shaft did not pass through these components. This not only reduces the weight of the operating unit but also simplifies assembly. The reduced number of bearings also means lower wear and higher reliability, as potential failure points such as bearing failure or misalignment are minimized. Finally, this structure also helps reduce vibration and noise. Because the steering shaft passes directly and continuously through the brake, force feedback actuator, and corner stop, mechanical resonance and vibration can be distributed more evenly.

[0088] Preferably, the telescopic slider can move linearly relative to the telescopic carrier via a first bearing (especially a linear bearing) and a second bearing (especially a linear bearing) spaced apart from it in the extension direction.

[0089] In this context, a minimum spacing of 80 mm between the first and second linear bearings on the telescopic load-bearing component is particularly preferred. This reduces potential tilting movements that may occur when the slider is subjected to lateral or vertical forces or uneven loads. This ensures that the operating unit is always precisely aligned, which is especially important during dynamic movements or under high system loads. A bearing spacing of at least 80 mm also allows for a more even distribution of load between the two bearings, reducing wear and load on individual bearing components. Furthermore, a bearing spacing of at least 80 mm also dampens vibrations and oscillations that occur during operation.

[0090] Attached image caption The present invention will be further described below with reference to the accompanying drawings, but is not limited to the embodiments shown in the drawings.

[0091] Figure 1 This is a schematic diagram of a motor vehicle equipped with a steer-by-wire system.

[0092] Figure 2 It is a perspective view of an operating unit.

[0093] Figure 3 It is an axial sectional perspective view of an operating unit. Detailed Implementation

[0094] Figure 1A steer-by-wire system (1) for a motor vehicle (2) is shown, equipped with a control device (45). The steer-by-wire system (1) includes an operating unit (4) located in the passenger compartment (141), which receives steering commands from a user or control device (e.g., which may be part of an automatic or semi-automatic driving system of the motor vehicle (2)) and transmits them as electrical or optical signals to the wheel actuators (6) of the front axle steering (3), which translate the corresponding steering commands into steering actions of the vehicle wheels (7a, 7b). Of course, steering commands can also be implemented through rear axle steering or single-wheel steering.

[0095] The operating unit (4), located in the passenger compartment (141), collects the driver's steering input via the control device (45) or receives corresponding signals from the vehicle control unit. After collecting the steering angle, torque, or other parameters via sensors, the signals are transmitted to the control electronics unit, which then transmits the steering command to the wheel actuators (6). The wheel actuators (6) convert the electrical or optical control signals into mechanical steering actions, preferably through linkages or direct drive to the vehicle wheels (7a, 7b) on the front axle, thereby achieving the required steering angle. Preferably, the wheel actuators (6) may also be equipped with other sensors to feed back road conditions, forces, or steering angles of each wheel to the control electronics unit. This enables adaptive control strategies, such as stabilizing vehicle driving in critical driving situations or initiating steering actions solely through the control device during autonomous driving. By eliminating the direct mechanical connection between the control device (45) and the steering mechanism, costs and space are saved, and vibrations or disturbances within the vehicle are reduced.

[0096] Figure 2 A perspective view of the operating unit (4) is shown. The operating unit (4) includes a telescopic sliding mechanism (46), which includes a tubular telescopic support (138) and a telescopic slider (137) that can move linearly therein. Figure 2 The telescopic sliding mechanism (46) is shown in the extended state of the telescopic slider (137).

[0097] By linearly moving the telescopic slider (137) within the tubular telescopic support (138), the axial position of the control device (45) relative to the driver can be precisely adjusted, thereby achieving optimal ergonomic distance. Figure 2In the illustrated embodiment, the telescopic slider (137) is mounted in the inner guide rail of the telescopic carrier (138) with low friction. The connection between the telescopic carrier (138) and the steering column adjustment device (42) also allows for adjustment of the tilt angle of the entire operating unit (4), enabling the driver to obtain a personalized seat and operating position. The steering shaft (43) is substantially coaxial with the telescopic slider (137) and the telescopic carrier (138), and protrudes at the end of the telescopic slider (137) near the control device. The control device (45) can be connected to this protruding shaft section, and the rotational motion of the control device (45) is transmitted to the steer-by-wire system or collected in the system via the steering shaft (43).

[0098] Figure 3 The internal structure of the telescopic slider (137) is shown. It can be seen that a force feedback actuator (41) is arranged inside the telescopic slider (137), which is equipped with a motor (109) and a brake (107), the brake (107) being a magnetorheological brake (108). In addition, an angle limiter (44) is also provided inside the telescopic slider (137). Figure 3 Clearly, the telescopic slider (137) is designed to compactly accommodate all the key functional components of the steer-by-wire system while providing axial adjustment functionality.

[0099] A steering shaft (43) passes through and connects to a steering angle limiter (44), a force feedback actuator (41) equipped with a motor (109) and a brake (107). Torque can be applied to the steering shaft (43) via the motor (109) and the brake (107). The torque generated or applied by the motor (109) is transmitted to the steering shaft (43), giving the driver an active steering feel and precise feedback through the steering wheel. A magnetorheological brake (108) is integrated into this force flow, achieving adjustable damping or braking torque by selectively changing the viscosity of its magnetorheological medium. This allows for stepless adjustment of the braking effect, enabling precise control of steering feel and self-centering force.

[0100] The angle limiter (44) provides a clear mechanical limit in each rotational direction of the steering shaft (43). The angle limiter (44) detects the position of the steering shaft (43) and mechanically ensures that a predetermined limit torque is reached in both rotational directions, thereby preventing the system from over-rotating or being damaged. Since the steering shaft (43) passes through not only the angle limiter (44) but also the motor (109) and brake (107), it ensures that all components are coaxially aligned, enabling high-precision, fast-response force and torque management.

[0101] pass Figure 2-3 It can be clearly seen that the operating unit (4) has a telescopic sliding mechanism (46), including a telescopic support member (138) and a telescopic slider (137) that can move linearly relative to the telescopic support member (138).

[0102] The steering shaft (43) is rotatably mounted inside the telescopic slider (137). The telescopic slider (137) contains an angle limiter (44) and a power-feedback actuator (41) with a power-operated motor (102) and a power-operated brake (107). The arrangement order of the brake (107), the power-feedback actuator (41), and the angle limiter (44) inside the telescopic slider (137) is as follows: from the end closer to the operating device, the angle limiter (44), the brake (107), and the power-feedback actuator (41) are arranged in sequence, towards the end away from the operating device.

[0103] The brake (107) is a magnetorheological brake (108), whose maximum heat output is at most 1 / 5 of the maximum heat output of the electric motor (102). The electric motor (102) is located in the area of ​​the telescopic slider (137) away from the operating device. The magnetorheological brake (108) is located in front of the electric motor (102) when viewed from the direction of the operating device (45).

[0104] The telescopic slider (137) is guided relative to the telescopic support member (138) by a first linear bearing (136a) and a second linear bearing (136b). The first linear bearing (136a) and the second linear bearing (136b) have thermal conductivity lower than that of the telescopic slider (137).

[0105] The thermal conductivity of the telescopic support component (138) is higher than that of the telescopic slider (137).

[0106] Figure 3 It is also shown that the steering shaft (43) is guided relative to the telescopic slider (137) by the first steering shaft bearing (133a) and the second steering shaft bearing (133b), and the thermal conductivity of the first steering shaft bearing (133a) and the second steering shaft bearing (133b) is lower than that of the telescopic slider (137).

[0107] The steering shaft (43) passes at least partially, preferably completely, through the brake (107), the force feedback actuator (41), and the angle limiter (44). The steering shaft (43) is fixed within the slider in the direction of extension of the telescopic slider (137).

[0108] This invention is not limited to the embodiments shown in the accompanying drawings. The foregoing description should not be considered limiting, but rather illustrative. The following claims should be understood as indicating that the described features are present in at least one embodiment of the invention. This does not exclude the presence of other features. If the claims and the foregoing description define "first" and "second" features, such designations are used only to distinguish two identical features and do not indicate any order of priority.

[0109] List of reference numerals 1 - Steer-by-wire system 2 - Motor vehicles 4 - Operation Unit 6 - Wheel actuator 7 - Wheels 41 - Force Feedback Actuator 43 - Steering Axle 44 - Corner limit switch 45 - Control Device 46 - Telescopic sliding mechanism 102 - Electric Motor 107 - Brake 108 - Magnetorheological brake 133a - First Steering Shaft Bearing 133b - Second Steering Shaft Bearing 136a - First Linear Bearing 136b - Second linear bearing 137 - Telescopic slider 138 - Telescopic load-bearing component

Claims

1. An operating unit (4) for a steer-by-wire system (1) of a motor vehicle (2), which can be connected to a control device (45) so that the steering action of the control device (45) is converted into a signal representing the steering action and transmitted to the wheel actuator (6) to realize the steering action through the wheels (7) of the motor vehicle (2), wherein, The operating unit (4) has a telescopic sliding mechanism (46), including a telescopic support member (138) and a telescopic slider (137) that is linearly movable relative to the telescopic support member (138), wherein a steering shaft (43) is rotatably mounted in and / or on the telescopic slider (137), and an angle limiter (44) and a power-operated feedback actuator (41) with a power-operated motor (102) and a power-operated brake (107) are provided in the telescopic slider (137). Its features are, The brake (107) is designed as a magnetorheological brake (108) with a maximum heat output of up to 1 / 5 of the maximum heat output of the motor (102), and the motor (102) is located in the far end region of the telescopic slider (137) on the side away from the operating device.

2. The operating unit (4) according to claim 1, characterized in that, The thermal conductivity of the telescopic slider (137) is greater than 40 W / m*K.

3. The operating unit (4) according to claim 1 or 2, characterized in that, The outer surface area of ​​the telescopic slider (137) is selected to be 40,000-100,000 mm². 2 Preferably 50,000-87,000 mm 2 .

4. The operating unit (4) according to any of the preceding claims, characterized in that, The average distance between the outer surface of the telescopic slider (137) and the telescopic support (138) is less than 5 mm.

5. The operating unit (4) according to any of the preceding claims, characterized in that, The magnetorheological brake (108) is positioned in front of the motor (102) when viewed from the direction of the operating device (45).

6. The operating unit (4) according to any of the preceding claims, characterized in that, The telescopic slider (137) is guided relative to the telescopic carrier (138) by a first linear bearing (136a) and a second linear bearing (136b), and the thermal conductivity of the first linear bearing (136a) and / or the second linear bearing (136b) is less than that of the telescopic slider (137).

7. The operating unit (4) according to any of the preceding claims, characterized in that, The thermal conductivity of the telescopic bearing (138) is greater than that of the telescopic slider (137).

8. The operating unit (4) according to any of the preceding claims, characterized in that, The steering shaft (43) is guided relative to the telescopic slider (137) by a first steering shaft bearing (133a) and / or a second steering shaft bearing (133b), and the thermal conductivity of the first steering shaft bearing (133a) and / or the second steering shaft bearing (133b) is less than that of the telescopic slider (137).

9. The operating unit (4) according to any of the preceding claims, characterized in that, The total mass of the telescopic slider (137) is 2-10 kg, preferably 2-8 kg, and more preferably 3-6 kg.

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