Steering device with magnetorheological brake mechanism and method of operating a steering device

Abstract

A steering device (100) for controlling a vehicle by means of a movable steering unit (301), wherein the movement of the steering unit (301) can be braked by means of at least one magnetorheological braking mechanism (1). The braking mechanism (1) includes a stationary support (4) and at least two braking components (2, 3). One braking component (2, 3) can be rotated through the steering unit (301). One braking component (2, 3) is non-rotatably connected to the support (4). The two braking components (2, 3) can rotate continuously relative to each other about a rotation axis (20). The first braking component (2) extends along the rotation axis (20) and includes a core (21) made of a magnetically conductive material. The second braking component (3) includes a hollow housing (13) extending around the first braking component (2). At least one surrounding slit (5) at least partially filled with a magnetorheological medium (6) is formed between the first and second braking components (2, 3). Here, the slit (5) includes two different braking slit portions (5a, 5b). A disc-shaped profile (41) is formed between the housing (13) and the core (21) in the first brake gap (5a), and a different disc-shaped profile (41) is formed between the housing (13) and the core (21) in the second brake gap (5b), or the gap (5) includes at least three brake gaps (5a, 5b, 5c).

Description

Technical Field

[0001] This invention relates to a steering device for controlling a vehicle by means of a movable steering unit, and a method for operating the steering device. The steering device includes a magnetorheological braking mechanism having a fixed support and at least two braking components that can rotate continuously relative to each other about a rotation axis. Background Technology

[0002] The requirements for this type of steering system are very high. For example, precise steering feedback and, especially, backlash-free or smooth steering behavior beyond the center position, as well as overall light and harmonious steering behavior, are required. Furthermore, the braking mechanism must be able to provide high braking torque, for example, for hard-end stops when the steering wheel is turned rapidly (i.e., high kinetic energy, when the steering wheel rotates rapidly, for example, at 1000° / s during back-and-forth motion). Because the number of operating parts in the steering wheel is significantly increased, the steering wheel becomes increasingly heavy, which increases kinetic energy. In addition, high braking torque is also required when the male (female) driver (or user) holds or supports themselves on the steering wheel when getting in / out of the vehicle (getting in / out assistance). This braking torque can be, for example, 25 Nm, 35 Nm, or higher.

[0003] Simultaneously, the braking mechanism must also provide very low braking torque (less than 1 Nm, preferably less than 0.5 Nm), for example, when only a very slight steering movement is required to maintain lane position when driving straight out. Similarly, low braking torque (e.g., 1 to 3 Nm) is needed when steering through the center position or changing direction, so that the vehicle can be controlled smoothly and quickly, and harmoniously, through curves. Overall, sensitive and precise steering can be achieved with only a very light steering mechanism. For this purpose, a braking torque of less than 1 Nm is desired, for example.

[0004] Furthermore, the different braking torques should be adjusted with high quality, as seamlessly as possible without perceptible transitions. Additionally, the braking torque should be adjusted with the shortest possible reaction time, for example, within less than 100 ms. Here, the structural space for the steering system is generally very limited, for example, in the dashboard of a modern vehicle with a head-up display.

[0005] The aforementioned requirements are technically difficult to achieve. One problem is that high braking torque generally requires corresponding friction diameters and structural dimensions, which in turn increases the base torque (also known as no-load torque). A high base torque is also contrary to the requirement of easy steering.

[0006] Therefore, for example, a known friction clutch provides a high maximum braking torque. However, the friction surfaces required to obtain the braking torque also result in a large basic friction when not energized, such as 1 Newton-meter basic friction at a maximum braking torque of 20 Newton-meters.

[0007] Furthermore, steering systems with electric motors are known, with the motor either directly connected to the steering wheel or via a reduction gear or a toothed belt. Such directly mounted motors generate, for example, an active braking torque (rated torque) of up to 8 Nm and a temporary passive braking torque of up to 25 Nm. However, due to the correspondingly high braking torque, these motors are large, bulky, and slow to respond (due to mass inertia), and are generally also expensive. Adjustability at low braking torques warrants improvement due to their wide operating range.

[0008] For example, an electric motor driven by a belt drive and mounted parallel to the steering branch (indirect mounting) should be designed favorably because the additional belt drive, pulleys, and brackets require space and cause flexibility, clearance, and additional costs.

[0009] The electric motor in the steering system must generate high braking torque primarily at low speeds, resulting in unfavorably high current or power demands. Simultaneously, the motor exhibits poor efficiency at low speeds or when stationary (e.g., to provide end stops) and therefore heats up quickly. This, in turn, further reduces efficiency due to increased coil resistance. Consequently, the motor heats up rapidly and all power demands increase quickly and strongly.

[0010] DE 10221241 A1 discloses a steer-by-wire device for motor vehicles having an electric motor and a magnetorheological brake.

[0011] Braking units with magnetorheological fluids have been disclosed in the prior art, such as Lord's MRF brakes in various structural sizes (5 Nm, 12 Nm, 20 Nm). They are often used as "steer-by-wire haptic feedback." The brake itself functions. However, a drawback of the MRF brake is its relatively high basic friction (basic torque) relative to its maximum torque (operating range). The operating range of the 5 Nm brake, according to Lord's website / manual, is 0.5 to 5 Nm (multiples of 10), the 12 Nm brake is 1 to 12 Nm (multiples of 12), and the 20 Nm brake is 1 to 20 Nm (multiples of 20). This relatively small operating range is insufficient for many applications, as these mass-produced products are primarily used in large motor applications (especially those requiring gloved operation, such as industrial, agricultural machinery, forklifts, etc.).

[0012] For (primarily) small motor applications such as passenger car steering, it is advantageous to maintain a much lower base torque while achieving a higher maximum torque, i.e., a significantly larger operating range. In particular, a high base torque can lead to fatigue or discomfort, for example, during steering. However, known MRF brakes do not allow for a large operating range due to their excessively large friction surface. While a smaller friction surface would reduce the base torque, the maximum torque would also be smaller, which is precisely what is disadvantageous in steering systems. Summary of the Invention

[0013] In contrast, the objective of this invention is to provide an improved steering mechanism. In particular, the steering mechanism should substantially meet the aforementioned requirements and preferably simultaneously provide reliable and safe functionality as well as economical manufacturing capabilities.

[0014] This task is accomplished by a steering mechanism. Other advantages and features of the invention are described in the overview and examples.

[0015] The steering device of the present invention is used to control (steer) a vehicle by means of a (at least sometimes manually) movable steering unit. The movement of the steering unit can be braked (especially damped) by means of at least one magnetorheological braking mechanism. The braking mechanism includes a stationary support and at least two braking components. At least one of the at least two braking components can be rotated by the steering unit. In particular, the braking component is rotatably engaged to the steering unit. At least another of the at least two braking components is non-rotatably connected to the support. The two braking components can rotate continuously relative to each other about an axis of rotation. A first braking component extends along the axis of rotation. This means that the first braking component extends at least partially along the axis of rotation. Or at least a portion of the first braking component, or preferably the main portion of the first braking component, extends along the axis of rotation. The first braking component includes a core made of a magnetically conductive material. The second braking component includes a hollow shell extending around the first braking component (especially radially and / or axially). At least one surrounding gap, at least partially filled with a magnetorheological medium, is formed between the first and second braking components. Here, the gap includes at least three (especially axially spaced and preferably surrounding) braking gap portions. Here, the brake slits can be designed to be the same or different. In particular, the brake slits can be configured to be the same or different in terms of their disc-shaped profile. Additionally or alternatively, the slit includes at least two different brake slits. The brake slits are formed particularly radially. Additionally or alternatively, the brake slits can also be formed axially. Here, a disc-shaped profile is formed between the housing and the core in or at the first brake slit. A disc-shaped profile different from that formed in the first brake slit is formed between the housing and the core in or at the second brake slit.

[0016] The steering device according to the invention offers numerous advantages. A significant advantage is that, for example, two separate coils (along with their corresponding brake gaps) are provided and can be controlled separately. This allows for better and more sensitive adjustment of the steering, and, as needed, with a high torque. Thus, braking can be adjusted, for example, at low speeds or when stationary, with one or the first coil (along with its corresponding brake gap), while the second coil (plus the brake gap) can be used to optimally modulate the torque, for example, at higher speeds. The adjustment of the respective current intensities and current profiles can be performed independently of each other.

[0017] It is particularly advantageous when the available electronic devices do not have a large settling period, as two (identical or sometimes different) coils can be adjusted independently of each other for different torques and speeds. This is, for example, the case in cars where the onboard electronics provide only limited power or voltage. There, the first coil (with a star-shaped profile, for example, within the brake slit) can be used for low braking torque, where a small torque (e.g., 0.1 Nm) should be generated with high resolution. The adjustable torque in this case is not speed-dependent (or only minimally dependent). The second coil can, for example, adjust or modify the magnetic field in other, such as second or third, brake slits for high locking torque or maximum torque, for example, for exit assist. Such high torque generally does not require high resolution, and speed dependence is not decisive in this case.

[0018] This invention, for example, allows for braking (locking) at a stop using an electric coil or (for which additional design) magnetic circuitry, thereby generating a very high braking torque. Here, reproducibility (in the high-torque stopped state) generally does not need to be very precise, which reduces structural complexity and cost. As long as the braking torque is sufficiently high and not exceeded, the stationary braking component will not rotate. Another electric coil or another magnetic circuit can then, for example, be designed to purposefully brake the corresponding braking component during rotation in continuous operation. This generally requires high reproducibility so that the difference is imperceptible or only slightly noticeable to the touch. In most cases, this requires higher structural requirements and may involve higher technical complexity and thus higher costs. This invention allows for both performance characteristics in a simple manner and generally allows for a low-cost design.

[0019] Preferably, at least one third brake gap is arranged axially between the first brake gap and the second brake gap. In particular, the first brake gap is equipped with at least one first electric coil, and the second brake gap is equipped with at least one independently controllable second electric coil.

[0020] Furthermore, the two differently formed disc-shaped profiles of at least two brake slits offer a significant advantage. Thus, for example, a low and precisely adjustable braking torque can be generated using the first brake slit. A very high braking torque can be generated using the second brake slit, for example, for end-stop or vehicle entry / exit assistance. A particular advantage is that both brake slits have a very small basic torque. Another advantage is that this braking mechanism requires only a small amount of structural space overall and is implemented uncomplicatedly and economically. Moreover, the steering mechanism of the present invention is particularly reliable because the brake slits allow for redundancy.

[0021] The first and second brake slits are preferably designed to be different in the radial (and / or axial) direction and / or functionally different. Preferably, the first and second brake slits are designed to have different widths (slit heights) and / or different cross-sectional profiles.

[0022] The second brake gap preferably has a gap height that varies within the brake gap area. In particular, the second brake gap has a disc-shaped profile designed with a star-shaped outline. The first brake gap preferably has a gap height that remains constant within the brake gap area. In particular, the first brake gap has a disc-shaped profile with a cylindrical outer geometry. It is also possible and preferred that the first brake gap has a gap height that varies less significantly within the brake gap area compared to the second brake gap. Thus, the first brake gap also particularly has a star-shaped profile.

[0023] In an advantageous preferred design, the steering mechanism includes at least one drive unit for generating driving torque for the active movement of the steering unit. In particular, the drive unit includes at least one electric motor. At least a major portion of the electric motor is arranged radially (preferably also axially) within an outer periphery defined by a slit (particularly a brake slit portion of a braking mechanism). Specifically, at least one rotor and / or stator of this electric motor is arranged within this outer periphery. The slit surrounds the electric motor, particularly radially and preferably also axially, with respect to its outer periphery.

[0024] This steering system can be used in motor vehicles (e.g., cars; SUVs), aircraft, flying machines, ships, boats, and in agricultural technology such as tractors or combine harvesters, harvesters, and other agricultural field machinery (SUVs). It can also be used in construction machinery and, for example, forklifts or similar machines, or in simulators used to simulate vehicle control (games; racing simulators; computer peripherals...). This steering system is particularly useful in vehicles that are at least sometimes autonomously driven.

[0025] The steering unit can be designed, for example, as a steering wheel, lever or steering column, control stick, control arm, control pedal, control lever or control wheel, or operating wheel. Other configurations of the active steering unit for a steering vehicle are also possible. The movement of the steering unit is, in particular, rotational movement. Specifically, the steering unit can move in at least two rotational directions. The movement of the steering unit can also be another type of movement. The steering mechanism may include at least one transmission mechanism adapted and designed to convert the movement of the steering unit into rotational movement of one of the components of the braking mechanism.

[0026] The preferred design among all options is one that allows for real-time adjustment of the braking torque.

[0027] In particular, the steering system includes at least one actuator device for converting steering motion performed by the steering unit into vehicle motion. Specifically, the steering unit and actuator device are only electrically and / or only electromagnetically connected. Specifically, the steering unit and actuator device (in normal operation) are not mechanically engaged. Mechanical engagement may be specified in normal operation. The steering system is particularly a steer-by-wire system. This also includes steer-by-wire systems that engage the steering branch in special circumstances such as emergency situations or fail-safe conditions, i.e., particularly where mechanical engagement exists between the steering unit or the driver and the wheels. In this design, the present invention offers particularly numerous advantages.

[0028] However, it is also possible to design the steering system as a mechanical steering system, preferably a servo steering system. In such a steering system, it is also advantageous to use two different brake gaps.

[0029] The braking mechanism, under the effective influence of the magnetorheological medium, possesses a braking torque. Under the ineffective influence of the magnetorheological medium, it possesses a fundamental torque. Here, the fundamental torque is at least 50 times smaller, preferably at least 90 times smaller, and particularly preferably at least 100 times smaller than the maximum braking torque available from the braking mechanism. This provides a wide operating range. This provides particularly advantageous steering behavior and can be well achieved using the braking mechanism proposed herein. The motion resistance of the steering unit is particularly characterized by a torque consisting of at least the braking torque and the fundamental torque.

[0030] It is possible and advantageous that the braking mechanism has a basic torque of up to 0.5 Nm, preferably up to 0.25 Nm, and particularly preferably up to 0.1 Nm, under the ineffective influence of the magnetorheological medium.

[0031] In particular, the braking mechanism can generate a maximum braking torque of at least 25 Nm, preferably at least 45 Nm, and particularly preferably at least 50 Nm through the effective influence of the magnetorheological medium.

[0032] In all designs, it is preferred and advantageous that a braking torque of at least twice that of a braking torque of at least two times ...

[0033] The first brake gap can generate only a portion of the maximum braking torque, preferably less than half. Specifically, less than a quarter, preferably less than one-eighth, of the maximum braking torque can be generated using the first brake gap. Furthermore, the braking torque generated by the first brake gap is between 0 Nm and 10 Nm, preferably between 0 Nm and 8 Nm, and particularly preferably between 0 Nm and 5 Nm. This braking torque can be adjusted with a very high degree of precision using the first brake gap.

[0034] The second brake gap is utilized, particularly the main portion that generates the maximum braking torque, preferably at least two-thirds of it. Specifically, at least three-quarters or even at least 90% of the maximum braking torque can be generated using the second brake gap. It is possible that the maximum braking torque is generated solely using the second brake gap. It is also possible that the first brake gap is used simultaneously with the second brake gap for support. In this braking torque configuration, the second brake gap can be advantageously employed because its performance and adjustability are conventionally not disadvantages in this case.

[0035] Preferably, and advantageously, the first brake slit can adjust the braking torque with a higher resolution than the second brake slit. Preferably, the first brake slit has a resolution at least 10 times higher than the second brake slit.

[0036] In particular, the first braking gap can generate braking torque with a resolution of at least 0.5 Nm, preferably at least 0.25 Nm, and particularly preferably at least 0.15 Nm.

[0037] Preferred and advantageous in all designs is that the first brake gap section is equipped with a first electric coil, and the second brake gap section is equipped with a second electric coil. In particular, these coils can be controlled independently. Specifically, the coils are used to generate a (magnetic) field to influence the magnetorheological medium. Furthermore, the coils can be controlled (especially intelligently) by a steering controller (described below). This design allows for very sensitive steering behavior and also provides reliable redundancy.

[0038] In the aforementioned design, it is preferred and advantageous that a lower braking torque can be generated using a single brake slit or only a portion of the brake slit. A higher braking torque is preferably generated using at least two brake slits or a larger portion or even all of the brake slits.

[0039] Alternatively, the at least two braking gaps can be powered by a unified coil. Thus, for example, at least one coil wound around the axis of rotation and surrounding the core could be positioned between the housing and the core.

[0040] In special / extreme or emergency situations, the electric motor can be switched on to provide additional maximum braking torque.

[0041] The steering system particularly includes at least one steering controller for controlling the braking mechanism. Specifically, the steering controller can adjust the braking torque of at least two brake gaps, particularly independently of each other. In particular, the steering controller is used to control the braking mechanism based on the position of the steering unit and / or based on the motion parameters of the steering unit and / or based on the vehicle's operating state and / or based on "data".

[0042] "Data" can be, for example, vehicle data such as vehicle speed, lateral acceleration; spatial attitude; braking value; GPS location; environmental recognition; data / location of other vehicles (in the vehicle environment); whether there is a trailer; passenger data (body size, weight, coat, posture, analytical data based on data evaluation using artificial intelligence and suggestions; noise, posture); external data (e.g., data sent from the driver's residence to the car; garage data in the garage, etc.).

[0043] The steering behavior of a person wearing a thick coat in winter differs from that of a person wearing a thin shirt in summer. The thick coat restricts movement and thus leads to different steering behaviors. If the control electronics detect this through "data," they can adjust the behavior; for example, quickly turning the steering wheel to avoid an obstacle is difficult (limited body movement) and slow in reality when wearing a thick, fitted coat. This can be addressed intelligently by increasing the ratio of the steering angle at the steering wheel to the steering angle at one or more wheels, allowing the avoidance process to still be quick. Furthermore, the required steering effort (assistance) can be reduced because the heavy housing acts as a damper.

[0044] If data-driven and / or near-field recognition detects, for example, driver fatigue and careless steering, this can be intelligently compensated for. In this case, the driver can be warned (by bumps or vibrations), or the steering unit can, with the aid of artificial intelligence, implement the driver's command (steering wheel) in a different way, i.e., the steering wheel movement is not performed in a 1:1 ratio with wheel adjustments. Therefore, on straight roads (highways), this can prevent the vehicle from "swerving" and swaying excessively.

[0045] On the other hand, this intelligent electronic device can identify fatigue and intervene (warning; deceleration until a stop; autonomous parking; etc.) based on data analysis (steering movements, facial recognition, comical driver gestures, temperature, breathing sounds, etc.). This is particularly advantageous in situations such as dizziness, blurred vision, or myocardial infarction.

[0046] Vehicle steering or movement can also be detected through data analysis to identify when children are being prevented from driving (force, grip, near-field recognition). In cases of doubt, steering torque can be temporarily increased to determine whether the driver is applying sufficient force when the vehicle is in use, while the child is not.

[0047] The vehicle (using machine learning / artificial intelligence / GPS data, etc.) knows, for example, that there is a pothole or obvious rut. The driver, due to this (vehicle movement, steering wheel pull, etc.), steers the vehicle unevenly or incorrectly (the rut is too close to the edge, etc.). At this point, the intelligent braking unit activates and "smooths" the unwanted or dynamically weakened steering movements, thus ensuring a smooth, safe, and comfortable journey to the destination.

[0048] Similar situations occur with snow, slippery surfaces, and rocks. The steering system is particularly adapted to these conditions, with active and passive torques adjusted accordingly. If a vehicle skids on slippery surfaces (snow, ice, etc.) while cornering in winter (e.g., due to understeer), the driver is likely to oversteer out of panic. Once the vehicle regains traction, it may oversteer, leading to an accident. In this case, the steering torque should be increased or (with tactile feedback, such as undulations) to alert the driver to oversteer.

[0049] The situation is exactly the opposite when drifting (especially in icy or snowy conditions during winter). Here, inexperienced drivers often turn too little and thus the vehicle "loses control" and skids. Steering can also be done very easily here, requiring oversteering.

[0050] Some people prefer to grip the steering wheel at the top (between 10 o'clock and 2 o'clock). This results in greater steering angle changes during vibrations, or the steering wheel is difficult to hold smoothly in this body posture, or it may swing upwards (also known as motion sickness). If the cabin monitoring system detects this grip, the torque can be increased slightly, resulting in a smoother ride.

[0051] Smaller individuals also have drastically different steering wheel grips compared to taller individuals, and their varying limb lengths result in different lever distances. Shorter arms often need to reach for the grip during larger steering wheel movements, leading to unstable steering maneuvers. If a grip or unfavorable kinematic arm position is detected (“data”, near-field recognition; rotation angle analysis...), a controller or artificial intelligence can, in particular, “smooth” the process, i.e., make it more coordinated.

[0052] This can also be advantageous when the driver has been traveling for a long time.

[0053] Tactile feedback can be provided when changing lanes. Different feedback is given for two lane changes. All of this is combined with "data" (such as navigation systems, environmental recognition, etc.). Steering, in particular, provides corresponding feedback.

[0054] This invention is also advantageous in situations where parking spaces or areas in urban areas or garages are expensive and should be utilized as efficiently as possible. Parking areas can be of varying sizes and ideally allocated to vehicles via data packets (radio, WLAN, 5G, etc.) upon entering the garage. During parking, the "smart garage" should support the parking process, i.e., setting the ideal parking posture and transmitting it to the parked vehicle. The intelligent steering system then executes the parking maneuver or suggests which vehicles the driver should accept and execute (e.g., when an unrecognized object in a parking space is present). The "smart garage" also knows and notifies adjacent vehicles whether a passenger is present, i.e., whether the vehicle can be parked close to the passenger door. The user of adjacent vehicles can also be stored and notified to the "garage" that they will return with the passenger. If a vehicle is parked for an extended period and is notified to the smart garage or parking space, and the adjacent vehicle is parked for a shorter period, it can even be parked close to the door, further saving parking space. In cases such as online ticketing in airport parking garages, parking time can now be accurately known.

[0055] The parking process, aided by steering mechanisms and the distance to the nearest vehicle, can also be optimized in a design to accommodate the required door opening angle, allowing drivers or passengers to easily get in and out. The vehicle uses "data" to determine the passenger's opening angle or body size. Similarly, a smart garage can detect / identify and intelligently allocate (use) the required distance.

[0056] If intelligent steering, based on "data," notices that it has entered an area it shouldn't (such as a pedestrian zone, bike lane, no-entry zone, building entrance, etc.), it can output tactile feedback until intervention (reverse steering; vehicle stops). However, it is preferable to always output warning feedback first, and the driver can also increase the pressure on this (i.e., no control, but mostly just a warning).

[0057] In particular, the position of the steering unit can be described by the rotation angle (which can be described relatively or absolutely). The motion parameters specifically include at least one characteristic parameter from a set of characteristic parameters, including: velocity; angular velocity; torque; acceleration (negative and positive); and duration. For example, targeted deceleration can therefore be performed during particularly rapid steering movements.

[0058] In order to control the braking mechanism based on the aforementioned parameters, at least one sensor device for measuring these parameters is provided. Specifically, the steering controller is effectively connected to at least one such sensor device. Position and / or motion parameters can be obtained using sensors at the steering unit and / or at the braking mechanism. For example, the braking mechanism includes at least one sensor device for measuring the relative position of a first component with respect to a second component.

[0059] Operating status is defined, in particular, by at least one of a set of characteristic parameters, including: vehicle speed; vehicle acceleration (negative and positive); wheel position; steering wheel position; steering gear rotation; load status; user size; user profile; external temperature; internal temperature; climate conditions; season; traffic conditions; road conditions or terrain conditions; and adjustment parameters of safety or auxiliary systems.

[0060] The steering controller is preferably adapted and designed to select at least one of at least two brake gaps based on the magnitude of the braking torque to be adjusted, and thereby brake the movement of the steering unit. In particular, the steering controller considers which braking torque can be generated to the maximum extent using each brake gap. Specifically, at least one numerical range of the braking torque to be adjusted is assigned to each of the at least two brake gaps. Depending on the numerical range of the braking torque to be adjusted, a suitable brake gap can be selected.

[0061] It is also possible and advantageous that the steering controller is adapted and designed to select at least two (or at least three or at least four) of at least three brake gaps based on the magnitude of the braking torque to be adjusted, and to generate braking torque by combination thereof.

[0062] The steering controller is preferably adapted and designed to generate braking torque for braking steering unit movement using at least primarily and preferably only the first brake gap when the vehicle speed exceeds a limit (and the vehicle is operating normally). This limit is, for example, 15 km / h or 25 km / h. At these or higher speeds, the braking torque must be adjusted with high resolution so as not to negatively affect steering behavior. This braking torque can be generated by combining at least two (or at least three or at least four) of at least three brake gaps.

[0063] The steering controller is particularly suited to and designed to lock the movement of the steering unit and generate the required braking torque primarily and preferably only by means of a second brake gap. In particular, the movement of the steering unit can be locked by means of a braking mechanism. This can provide a steering wheel lock. It can also provide support possibilities at the steering unit. For example, the locked steering unit can be used to stop the vehicle when getting out and / or getting in. This braking torque can be generated by combining at least two (or at least three or at least four) of at least three brake gaps.

[0064] In particular, the steering controller is adapted and designed to generate, at least primarily and preferably only, an end stop for the movement of the steering unit using the second brake gap. This end stop is generated, for example, when the wheel or steering wheel reaches the end of its prescribed travel. This end stop can be generated by combining at least two (or at least three or at least four) of at least three brake gaps.

[0065] Steering mechanisms may include, for example, a steering wheel. Most vehicles incorporate various functions into the steering wheel, such as keys, knobs, and wheels for operating the onboard computer, but also include displays, steering wheel heaters, etc., all of which require electricity and must receive and transmit signals. Electrical connections can be established, for example, through friction contact, induction, radio waves, or springs.

[0066] Advantageously and preferably, the steering controller is adapted and designed to brake or even lock the steering unit's activity based on the driving assistance system's braking. This prevents dangerous steering movements. In particular, the steering controller selects and controls at least one of at least two braking gaps for this purpose. For example, a first braking gap is selected for sensitive braking, and a second braking gap is selected for locking. For example, the steering controller can select and combine at least two (or at least three or at least four) of at least three braking gaps for this purpose.

[0067] As a driver assistance system, a lane keeping system can be set up, for example. Therefore, braking the steering unit can prevent leaving the lane or provide a warning indication to the driver (e.g., undulation). Additionally, when the driver assistance system identifies dangerous driving conditions and, for example, vehicle skidding, it can prevent tactile steering movements and / or overshoot caused by targeted braking of the steering unit.

[0068] Driving assistance systems can also include parking assistance. This can be achieved by braking or locking the steering unit, for example, to prevent the wheels from contacting obstacles (curbstones). In particular, the steering controller and / or driving assistance system includes at least one sensor device (surround view; image recognition; radar, lidar, etc.) for recognizing such conditions. This sensor device can, for example, include an environmental sensor system and / or a GPS system.

[0069] It is possible that the steering controller is adapted and designed to take user characteristics into account when adjusting braking torque. For example, user characteristics may include seating posture, user body size, user weight, user clothing, and / or whether the user is capable of driving. User characteristics can be stored in a user profile and / or measured using sensors. For example, near-field recognition devices and / or an internal camera (e.g., with image / facial recognition capabilities) could be incorporated for this purpose.

[0070] This steering controller is particularly well-suited for and designed to adjust the braking torque based on the position of the steering unit. Therefore, a higher braking torque can compensate for adverse stops of the steering unit, preventing unwanted steering movements, for example, at potholes.

[0071] Preferred and advantageous in all designs is a steering controller adapted and designed to generate tactile feedback at the steering unit. This feedback typically includes a prescribed sequence of braking torques. For example, this feedback can be perceived as vibrations at the steering unit. Shaking and / or undulations may also be perceived. It is possible that this braking torque can be generated at an adjustable frequency. This feedback can be generated particularly based on the position and / or motion parameters of the steering unit and / or the vehicle's operating state and / or the user's characteristics. For example, this feedback can be used to warn of dangerous maneuvers or to awaken someone experiencing fatigue. This feedback can also be used as a lane-changing signal.

[0072] Preferred in all designs, the steering controller is adapted and designed to use at least one machine learning algorithm (also known as artificial intelligence) to identify user behavior and take it into account when adjusting braking torque. For this purpose, data is continuously recorded and evaluated. Thus, for example, the movement of the steering unit can be damped based on existing muscle strength, fatigue, or driving behavior. Image recognition devices can aid in this. If it recognizes a contorted posture (a specific gait) such as when parking, the assistance capability can be improved. It is also possible to consider changes in the steering system or other vehicle components due to aging.

[0073] The magnetorheological medium preferably comprises at least one metal powder. In particular, the metal powder has a volume proportion of at least 50%, preferably at least 60%, or at least 70%. Using this medium, a very small fundamental torque can be obtained. Simultaneously, a very high maximum braking torque can be obtained based on the high volume proportion. Furthermore, this medium can be used with unchanged performance at the expected temperature of the steering device. The powder is particularly contained in a gaseous carrier medium, such as air.

[0074] The metal powder is preferably designed as carbonyl iron powder (pure iron) or contains at least this carbonyl iron powder. Other magnetorheologically responsive powders are also possible.

[0075] The metal powder is particularly preferably equipped with a coating.

[0076] The steering mechanism may include at least one reluctant magnetic mechanism and / or at least one permanent magnet unit, adapted and designed to maintain braking torque even when no current is supplied, utilizing at least one of the at least two brake gaps. The reluctant magnetic mechanism is particularly effectively connected to the steering controller. Specifically, the reluctant magnetic mechanism is provided via at least one of the coils.

[0077] The steering mechanism may include at least one safety device. This safety device is particularly suitable for and designed to at least partially expel the magnetorheological medium from the gap. Specifically, the safety device can expel the medium to such an extent that the steering unit is substantially free to move. Furthermore, the safety device can eliminate braking torque and / or fundamental torque. For example, the magnetorheological medium is expelled from the gap by means of positive and / or negative pressure. The safety device may include at least one pressure vessel and / or a detonator (Sprengkapsel), etc. This safety device serves as an emergency system (so-called fail-safe mechanism) in the event of brake mechanism interference.

[0078] In all designs, it is particularly preferred that the braking mechanism, especially the first and / or second components and / or the gap, has a maximum diameter of less than 100 mm (especially at a maximum braking torque of at least 25 Nm). This allows the braking mechanism to be installed with particularly minimal structural space (e.g., in an instrument panel). The braking mechanism proposed herein is particularly well suited to this maximum diameter.

[0079] Preferably, in all designs, the steering mechanism includes at least one drive unit for generating a driving torque for the active movement of the steering unit. This drive unit is particularly used to generate a driving torque that the steering unit must overcome to be manually moved. The drive unit can also be used to return the steering unit to its basic position. In particular, the drive unit includes at least one electric drive unit, such as an electric motor. The electric motor can also be a disc rotor motor, a traveling wave motor, or an axial flow motor. Additionally or alternatively, the drive unit may also include at least one accumulator and, for example, a spring.

[0080] In particular, the maximum braking torque of the second braking gap should be at least twice the maximum driving torque of the drive unit. Specifically, the drive unit should be able to generate a maximum driving torque of less than or equal to 12 Nm, and preferably less than or equal to 8 Nm.

[0081] The braking mechanism is preferably capable of providing braking torque in the event of drive failure, and the braking torque is at least as large as its driving torque. This steering system is particularly safe and reliable because the two braking gaps, together with the possibility of compensating for drive failure, provide triple redundancy.

[0082] The braking mechanism presented herein, when combined with the drive unit, offers the following particular advantages: the size of the drive unit and, for example, the electric motor, can be significantly reduced. Furthermore, all torques that should be passively applied are borne by the braking mechanism. This results in energy savings, which is particularly advantageous in the case of electric vehicles.

[0083] A much smaller (weaker) electric motor can prevent the driver from easily taking their hands off the steering wheel even in the event of misoperation (such as a faulty sensor signal). In addition, when an unreliable condition is detected (the electric motor will be clearly effective, even though the vehicle is traveling at high speed on the highway), the magnetorheological braking unit can counteract and over-brake the electric motor.

[0084] Preferably and advantageously, the steering controller is adapted and designed to compensate (adjust) fluctuations in the drive torque of the drive unit, at least approximately by adjusting the braking torque (especially by means of a first brake gap). In particular, the fluctuations can be compensated to such an extent that they are not tactilely perceptible on the steering unit. These fluctuations particularly relate to changes in drive torque with the rotation angle. Specifically, the steering controller is adapted and designed to adjust the drive torque substantially constant within the rotation angle range.

[0085] The disc-shaped profile may include at least one star-shaped profile. Specifically, a variable gap height is achieved within the braking gap region, particularly in the star-shaped profile area. Multiple magnetic field concentrators are arranged specifically at the star-shaped profile. Furthermore, the magnetic field concentrators radially protrude into the braking gap. This star-shaped profile reduces the frictional surface between the relatively rotating parts, thereby exhibiting a very small fundamental torque. Simultaneously, the star-shaped profile creates a so-called agglomeration of magnetorheological media, which allows for a very high braking torque.

[0086] In a particularly preferred and advantageous design, at least three brake slits are provided. Specifically, at least one third brake slit is provided axially between the first and second brake slits. Specifically, the first brake slit is equipped with at least one first coil, and the second brake slit is equipped with at least one independently controllable second coil. Specifically, the third brake slit is equipped with both the first and second coils.

[0087] Providing redundancy in such a system with two coils is also advantageous. When one coil fails, the other can still generate a magnetic field, thus providing adjustable torque (although not always of the same quality) through its corresponding brake gap. Redundancy is extremely beneficial for applications requiring high fail-safety.

[0088] At least two brake slits with different (functional) designs (especially in the radial and / or axial directions) may be provided. The brake slits may be configured separately from each other, and in an advantageous design, they may be axially separated from each other.

[0089] It is also possible that at least partially different materials are used in the first and second brake gaps. Particularly in the region of the first and second brake gaps, the materials used in the core and / or housing are at least locally different. The same or different materials and structures may be used for the electric coil.

[0090] These two brake slits can have different working clearances and slit sizes and / or slit profiles and orientations (relative to the moving parts). Smaller slit heights can result in higher torque, but are generally difficult to control technically. Larger slit heights generally have the opposite effect (lower torque but better adjustability). Therefore, depending on the requirements, either the (first) coil or the other (second) coil (electromagnetic coil) can be energized. Thus, end stops (stops, blockages) often require very high torque and small adjustment bases because the actuator is almost stationary. Here, a small slit (slit height) or possibly a rotating body / roller within the brake slit is efficient. Conversely, maintaining a relatively constant braking speed at higher speeds generally requires high adjustment quality, where a larger slit height and / or disc / star profile at the brake slit is advantageous.

[0091] The first braking component defines the axial direction. In particular, the axis of symmetry of the first braking component is the axis of rotation. Preferably, the core of the first braking component extends axially, but it may also be at a slight angle relative to the axial direction.

[0092] This invention allows for the generation of high braking torque at different rotational speeds with limited structural space. The magnetic field passes through two distinct braking gaps between the core and the casing, substantially radially or at least transversely to the axis of rotation.

[0093] In a preferred improvement, the first and second coils are designed to be different. The first and second coils are preferably different in at least one of a set of parameters, which includes wire diameter, wire shape, number of windings, winding window, coil width, coil diameter, and material.

[0094] Preferably, the radius or (general or maximum) diameter of the first brake gap is approximately, and especially exactly, the same as the radius or (general or maximum) diameter of the second and / or third brake gaps. This allows for the generation of high torque even at higher speeds and when starting from a standstill.

[0095] The magnetorheological medium, in particular, at least partially wets the first and second braking components.

[0096] The first and second coils are preferably wound around the axis of rotation and generate a magnetic field essentially axially within the core. These two coils are radially housed between the core and the housing. The coils can be wound onto the core or fixed to the housing on the inside.

[0097] The core is made of a (good) magnetically conductive material. The first braking component includes the core and, in particular, a shaft or rod, which is at least partially or entirely made of a non-magnetically conductive material. Preferably, the shaft (rod) and the core are detachably connected to each other.

[0098] The disk-shaped profile is at least partially or entirely made of a (good) magnetically conductive material.

[0099] In a preferred embodiment, the disk-shaped profile is designed as a separate disk body. Alternatively, the disk-shaped profile may be designed integrally with the core and, for example, T-shaped, with the long arms of the T-shape extending along the axis of rotation. It is also possible that a portion of the disk-shaped profile is integrally formed with the core and supplemented by a separate disk body. In a simple, particularly preferred design, the disk-shaped profile consists of a separate disk body fixed to or above the core.

[0100] The disc-shaped body is preferably mounted onto the core. For this purpose, the core particularly has a fitting groove. It is possible and preferred, for example, that the disc-shaped body is connected to or pressed against the core. However, it is also possible that the disc-shaped profile or disc-shaped body is connected to the housing and, for example, pressed into it. It is also conceivable to use two mutually mating disc-shaped bodies, forming a radial braking gap between them. Here, a first hollow cylindrical disc-shaped profile can be mounted onto the core, and a second hollow cylindrical disc-shaped profile with a correspondingly large inner diameter can be inserted into the housing, so that the two disc-shaped profiles are aligned with each other, for example, axially, leaving a small (radial) gap between them. A braking gap, particularly formed substantially radially, is thus left between the two disc-shaped profiles.

[0101] In a particularly preferred design, the disc-shaped profile has at least one disc assembly. The disc assembly is particularly formed by a plurality of disc-shaped plates preferably in close contact with each other. This design, for example, allows the disc-shaped plates to be machined as punching parts. Punching parts can be easily and inexpensively mass-produced. If they overlap and, for example, press against each other, a disc assembly or a disc body with a significantly thicker disc can be provided simply and inexpensively. Thus, both disc-shaped plates and disc assemblies can be manufactured very inexpensively.

[0102] Preferably, at least several, almost all, or all of the disk plates are designed to be circular and have the same or similar diameter. However, several or more non-circular disk plates may also be used, with non-circular outer contours, toothed structures, or star structures formed radially outwards. Overlapping circular and non-circular disk plates into a disk group can produce a complete outer contour, which may result in significant local magnetic field concentration. It is also possible that the disk group comprises multiple circular (or non-circular) disk plates with different outer diameters. Therefore, circular disk plates with smaller and larger diameters can be alternately arranged.

[0103] Some disks can also have different properties (e.g., due to different materials). Some disks can also be made of (sintered) magnetic materials (e.g., neodymium).

[0104] In a particularly preferred design, the disk-shaped profile generally has a cylindrical outer profile. It is also possible and preferred that the disk-shaped profile includes a star-shaped profile or is designed as a star-shaped profile.

[0105] It is possible and preferred that the disc-shaped profile has an outwardly convex outer profile on at least one axial side. The disc-shaped profile can generally be designed as conical, convex, rounded, or stepped. In particular, the disc-shaped profile is designed to be rotationally symmetrical within the outer profile region. The outwardly convex outer profile can, for example, be supported on or guided thereon on a cover. The outwardly convex outer profile thus allows for the provision of a magnetorheological particle storage device.

[0106] Preferably, the radial clearance in the second brake slot and the slot height in the first brake slot at the disc-shaped profile, as well as the slot height in the third brake slot (significantly), are smaller than the radial distance in other areas of the slot. The radial distance (in the axial direction) from the outer diameter of the coil or the outer diameter of the covering or coil enclosure to the radial inner wall of the housing is preferably (significantly) greater outside the two brake slots than inside them. The dimensional difference can reach or far exceed 2 or 3 times.

[0107] Because the gap is very small, in many cases, a separate support can be omitted, at least at the end with the disc-shaped profile. The disc-shaped profile then serves together with the housing to guide or support the housing relative to the core. This allows for a simpler and less expensive structure.

[0108] In all designs, the inner profile and / or preferably the casing can be non-circular (e.g., elliptical). The core can also be mounted eccentrically relative to the casing. This results in a varying relative gap at a specified position during rotation (of the rotor relative to the stator).

[0109] In a particularly preferred design, the electric coil is arranged axially between the first and second brake gaps. More preferably, at least one brake gap is axially adjacent to one of the electric coils, either indirectly or directly.

[0110] In all designs, it is particularly preferred that the magnetic field of the magnetic circuit passes at least partially axially through the core and the housing, and a substantial portion, particularly preferably substantially radially, passes through the third braking gap. Furthermore, a substantial portion, particularly preferably substantially radially, of the magnetic field of the first coil passes through the first braking gap, while the magnetic field of the second coil passes through the second braking gap. In a simpler design, each coil is wound around the core and generates a magnetic field within the core axially along the axis of rotation. The magnetic field is radially outwardly conducted at its respective end and exits at one axial end through a disc-shaped profile and the first or second braking gap, entering the housing from the core or vice versa at the other axial end through the third braking gap. This design allows for a particularly simple, low-cost, and efficient structure.

[0111] Particularly preferred is that the disc-shaped profile rotatably guides the housing and serves as a support.

[0112] Preferably, a closed cavity is formed between the braking components. In particular, at least a considerable portion of the closed cavity, and especially substantially, is filled with a magnetorheological medium such as a magnetorheological fluid and / or, for example, (dry or powdered) carbonyl iron powder. In particular, the second braking component is rotatably accommodated on the first braking component.

[0113] The first braking component preferably includes a shaft, which is at least partially made of a non-magnetic material. A core made of a magnetic material is fixed on the shaft or on an internal component.

[0114] Preferably, the second braking component is axially movably housed on the first braking component. This can, for example, also be used to achieve volume compensation in the event of temperature changes and / or leakage. Preferably, the relative radial and / or axial positions of the two braking components are measured using sensors.

[0115] It is preferred and advantageous to obtain the (especially absolute) position of the steering mechanism. In particular, the (especially relative) position of the braking components can be obtained. It is especially important to obtain not only the relative position of the braking components but also the absolute position of the steering mechanism, because the steering mechanism can have electrical terminals, such as coil springs, and these will not break. For this purpose, at least one absolute sensor is installed to identify the end of the steering stop. The brakes then specifically generate an end stop. The absolute sensor is also particularly necessary when the vehicle is parked and the steering wheel cannot be turned in neutral. When the vehicle is put back into use, the steering controller can thereby identify the turning angle of the wheels.

[0116] Torque sensors can also be installed in steering branches or steering shafts.

[0117] In all designs, it is preferable to position the clicker at one end of the cavity, particularly at the distal end. This clicker, in particular, allows for two states, where, after clicker operation, for example, the plate is audibly and / or tactilely switched and simultaneously performs a (small) axial displacement. This clicker, designed, for example, as a snap-action element or snap-action plate, is known from a keyboard or other device and allows for inexpensive and effective perceptible feedback during key presses, etc.

[0118] The click element is preferably disposed at one end of the cavity. Particularly preferably, an elastic membrane separates the cavity from the click element. The click element can be designed as a snap-action element or snap-action plate. This provides volume compensation at the cavity when the shaft is further inserted into or withdrawn from the cavity.

[0119] In a particularly preferred improvement, the sprocket is designed such that the change in the volume of the sprocket between its two states is adapted to the cross-sectional area of ​​the shaft multiplied by the shaft misalignment of the sprocket during operation. Specifically, the two volumes differ by less than 50% or 25%, and preferably less than 10% or less than 5%. This design of the sprocket adapting to the shaft allows for the provision of only a small volume, or possibly no volume at all, for volume compensation during sprocket operation.

[0120] The use of a clicker or quick-acting element on the far end of the cavity, which is also designed with a disc-shaped profile near the far end of the cavity, allows for particularly simple and effective guidance and support of the housing, because there is only a small radial clearance and the disc-shaped profile can therefore undertake (in many cases) sufficient guiding work in the radial direction of the housing.

[0121] The preferred improvement includes a sensor device or at least one sensor device for detecting the relative rotation angle between the core and the housing.

[0122] Preferably, it includes a sensor device or at least one sensor device for detecting the relative axial position of the housing relative to the core. This sensor device or at least one sensor device particularly preferably includes at least one magnetic field sensor designed to detect rotational angle and axial position. In a particularly advantageous design, the sensor device includes at least one Hall sensor.

[0123] In a simple, preferred design, the magnetic field sensor is housed on a stationary braking component and subjected to a radially acting magnetic field. The rotation angle can then be determined by the orientation of the magnetic field sensor relative to the magnetic field. The axial displacement of the sensor device relative to the housing can be derived from the strength of the magnetic field.

[0124] Particularly preferably, it includes at least one shielding mechanism for at least partially shielding the sensor device from the magnetic field relative to the coil. The shielding mechanism preferably includes at least one shielding body. The shielding body is particularly designed to shield the magnetic ring unit used to apply a prescribed (e.g., radial) magnetic field to the magnetic field sensor from the interfering magnetic effects of the coil. For this purpose, the shielding body preferably partially surrounds the magnetic ring unit. Preferably, the shielding mechanism surrounds the magnetic ring unit on three sides, i.e., from both axial sides and radially outwards. The shielding mechanism preferably includes at least one separating unit arranged between the shielding body and the magnetic ring unit. This separates the magnetic field of the magnetic ring unit from the shielding body. Additionally, it preferably includes at least one magnetic decoupling mechanism arranged between the shielding body and the housing. The separating unit and / or the decoupling mechanism preferably have a magnetic conductivity many times smaller than that of the shielding body. Preferably, the shielding mechanism and the magnetic ring unit are arranged spaced apart from each other.

[0125] Shielding mechanisms can significantly improve measurement quality. In particular, they enable the acquisition of fine angular resolution and small axial distances.

[0126] The control of the magnetic coil is preferably performed mostly or primarily during the operating time at a voltage, especially 12 volts. It is particularly advantageous tactilely (usually) that the braking torque of the magnetorheological braking mechanism reaches its maximum or set value as quickly as possible. This can sometimes only be achieved with a higher voltage. Maximum braking torque is typically obtained through the maximum magnetic field within the braking gap. Because the magnetic field is generated by the current within the electric coil (magnetic coil), the current must also be adjusted to its maximum value as quickly as possible. In principle, the voltage can always be adjusted to a high value, in specific cases not to, for example, 12 V but to, for example, 24 V. However, all components (electric or magnetic coil, coil wire, etc.) must be designed accordingly (and, for example, using wire with a larger diameter).

[0127] Therefore, in the preferred design and improvement scheme, a higher voltage (higher than required for sustained operation) is adjusted only at the onset of haptic feedback. Specifically, at or almost immediately after the onset of haptic feedback, the higher voltage is preferably set for a period between 0.5 ms and 50 ms, preferably between 1 ms and 20 ms, and especially preferably between 5 ms and 15 ms (e.g., 1.1, 1.2, 1.5, 2, or 3 times higher than required for sustained operation). The higher voltage is maintained until the current (or magnetic field) reaches the desired subsequent or maximum value (approximately, for example, 90% or 95%) and / or reaches or exceeds the period during which the higher voltage can operate. The voltage is then reduced to a lower voltage, for example, 12 V. The system reacts more quickly and adjusts to the desired braking torque more rapidly.

[0128] Especially in modern electric vehicles, multiple voltages exist and high voltage / current can be achieved, so they do not need to be precisely generated or converted. Electric vehicles can also have much higher voltages (such as up to 800 volts) and current intensities, allowing the aforementioned properties to be utilized advantageously.

[0129] In particular, the magnetic field strength between individual magnetically polarizable particles of the magnetorheological medium is greater than 300 kA / m. In particular, the magnetic field strength generated within the gap, preferably at least one of the braking gaps, is greater than 500 kA / m.

[0130] In particular, the steering mechanism includes at least four brake slits. Specifically, at least one common coil is provided for every two brake slits.

[0131] The steering system may include at least two magnetorheological braking mechanisms. In particular, the braking mechanisms can brake the movement of the same (unique) steering unit. The braking mechanisms are mechanically and / or electrically connected to each other for this purpose.

[0132] The method of this invention is used to operate a steering device using a magnetorheological braking mechanism with two braking components, wherein the two braking components are rotatable relative to each other about a rotation axis, wherein the first braking component extends along the rotation axis and includes a core made of a magnetically conductive material, and wherein the second braking component includes a hollow shell extending around the first braking component, wherein at least three axially spaced and surrounding braking gaps, at least partially filled with a magnetorheological medium, are formed between the first and second braking components. Here, a first coil generates a (first) controllable magnetic field in the first braking gap. Conversely, a second coil generates a (second) controllable magnetic field in the second braking gap, so as to produce braking forces of different intensities, particularly depending on the rotational speed. Here, the magnetic fields of the first and second coils are confined, in particular, by the third braking gap.

[0133] The method according to the invention also advantageously accomplishes the aforementioned tasks. The method is particularly designed to operate the steering mechanism of the invention accordingly. In particular, the steering mechanism can be operated according to the method of the invention.

[0134] Within the scope of this invention, locking specifically refers to the absence of movement of the specific unit (in at least one rotational direction and / or in two (all) working rotational directions) accompanied by the manual force required for operation. The movement of the steering unit can also be released, particularly by means of this braking mechanism. Within the scope of this invention, release specifically refers to the presence of a basic working torque (also known as an unloaded torque) of the braking mechanism, without the presence of additional magnetorheological delays caused, for example, by coil energization. When the movement is released, the magnetorheological braking mechanism is particularly ineffective, and therefore no field is generated to effectively influence the magnetorheological medium. Attached Figure Description

[0135] Other advantages and features of the present invention arise from the embodiments explained below with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram of a steering device with a magnetorheological braking mechanism according to the present invention is shown; Figure 2 A side view of the braking mechanism is shown; Figures 3a to 3c The cross-sections of the braking mechanism are shown; Figures 4a to 4b A highly schematic view of the sensor device and measurement results is shown; Figure 5 A highly schematic view of the braking mechanism along with the speed-actuating plates in different positions is shown; Figure 6 Two different designs of electric coils are shown; Figures 7a to 7b Another tactile braking mechanism is shown in cross-sectional and perspective views; Figure 8 A cross-sectional schematic diagram of another braking mechanism 1 is shown; Figure 9 A highly schematic circuit for controlling an electric coil is shown; Figure 10 A sketch is shown, which includes a braking torque curve to illustrate how the braking mechanism works. Figure 11 Another sketch containing the braking torque curve is shown. Detailed Implementation

[0136] Figure 1 A steering device 100 according to the invention is shown for steering a vehicle (not shown in detail herein) by means of a steering unit 301. The steering unit 101 is designed herein as a rotatable steering wheel, which is non-rotatably connected to the steering shaft 311.

[0137] The steering system 100 is designed as a steer-by-wire system. For this purpose, an actuator device 303 is employed to convert the steering motion achieved by the steering unit 301 into vehicle motion. For example, the actuator device 303 steers this or these wheels. The actuator device 303 is electrically connected only to the steering unit 101.

[0138] The rotational movement of the steering unit is measured by means of sensor device 70 and, for example, a rotation angle sensor. Based on the rotation angle, actuator device 303 then steers, for example, this or these wheels. Thus, for example, the front wheels and / or also the rear wheels can be steered, or in the case of a tricycle, the tricycle's tilting posture can also be achieved. Thus, it is also possible to steer the wheels of the front and rear axles, or even all axles (so-called crab walking).

[0139] Here, a drive unit 307, designed as an electric motor, is coupled to the steering shaft 311. The steering unit 301 can be actively rotated by the drive unit 307. Thus, the steering unit is actively moved, for example, when driving in a curve, just as it would be in a conventional mechanical steering system.

[0140] The movement of the steering unit 101 can be purposefully braked by means of the magnetorheological braking mechanism 1. A steering controller 302 is provided here to control the braking mechanism 1 and the drive unit 307 according to various parameters and, for example, the steering angle. For this purpose, the steering controller 302 is effectively connected to the sensor device 70.

[0141] The steering controller 302 also considers data from the driver assistance system 304, for example. This allows it to purposefully influence the movement of the steering unit 301 based on driving conditions. The steering controller 302 can also be effectively connected to other sensors not shown in detail here, so that steering characteristics can be selectively influenced based on other parameters.

[0142] The braking mechanism 1 is equipped with a safety device 306, which discharges the magnetorheological medium 6, which is also invisible here, through a gap 5. Therefore, the braking torque can be smoothly and reliably canceled, for example, in the event of disturbance. The gap 5 and the medium 6 are shown in detail with reference to the following figures.

[0143] Figure 2 A side view of the braking mechanism 1 with a support 4 is shown, which can be fixed to the bracket 50, for example, by a nut 51. The braking mechanism 1 has two braking components 2 and 3. Figure 2 The inner brake component 2 is not visible in the image. The inner brake component 2 is connected to the support 4. The support 4 and the inner brake component 2 are designed to be fixed in place. Another brake component 3 includes a housing 13 and is rotatably housed on the first brake component 2.

[0144] The braking mechanism 1 has a compact structure and includes, within the shielding mechanism 75 which is a shielding body 76 in two parts, a sensor device 70 for detecting the rotational and axial positions of the housing 13, which is not visible here. The housing 13 is connected to the left cover 14 and the right cover 15 by means of pins 16 to seal the internally closed cavity 10.

[0145] exist Figures 3a to 3c For example, it is drawn in the middle. Figure 2 A possible cross-section of the braking mechanism 1. A braking component 2 is housed on the support 4, which extends axially and is fixed to the core 21. The core 21 is radially surrounded by a (magnetic) housing 13, which serves as an outer braking component or a second braking component 3.

[0146] The magnetic core 21 is surrounded by two coils 26 wound around the core 21. The first coil 261 extends through an axial width 26e. A disc-shaped profile 41 is formed at one end of the core 21 facing the support 4, and the disc-shaped profile is mounted on the core and, for example, pressed. The disc-shaped profile 41 has a disc-shaped body 42 designed as a hollow cylinder. The grooves on the core can also be designed to be non-circular.

[0147] The core 21 can be made of sintered material (metal). The core can therefore be easily manufactured in the desired shape.

[0148] The disk-shaped body 42 is composed of a disk assembly 44, which is formed by multiple thin disk-shaped plates 46. Here, the disk-shaped plates 46 are designed as punched parts and can be punched from magnetically conductive metal plates with a thickness of 1 mm, 2 mm, or 3 mm, for example. Thus, the required number of disk-shaped plates can be punched out simply and inexpensively to produce the desired thickness of the disk-shaped body 42.

[0149] Several disc-shaped plates 46 are pressed together and mounted on the core 21, and are therefore connected or pressed together, for example, by threads. In the region of the disc body 42, a brake slot 5a with a small gap height 41b is provided between the outer diameter of the disc profile 41 and the inner circumferential surface of the housing 13. The axial width 41e of the disc profile 41 or its brake slot 5a is determined here by the number of disc-shaped plates 46 and can be selected to be greater than or less than those shown.

[0150] The disc-shaped profile 41 is axially adjacent to the first coil 261, which is housed in the coil holder 26b and is completely sealed radially outward by the filler 28.

[0151] The disc-shaped body 42 is connected to the core 21 and the stationary braking component 2 and does not rotate during operation. This allows holes or recesses to be formed so that cables 45 for electrically connecting the first and second coils 261, 262 can pass through. The coils 261, 262 can thus be connected simply, inexpensively, and quickly.

[0152] Here, a disc-shaped profile 41 is formed at the proximal end, i.e., the end of the core 21 facing the support 4. A second braking slit portion 5b is formed at the distal end, i.e., the other end of the core 21. The second braking slit portion 5b extends through an axial width 11e. A disc-shaped profile 41 is also provided there, which is formed here similarly or identically to the disc-shaped profile 41 at the proximal end in terms of its geometry. However, it is also possible that the disc-shaped profile 41 here is formed differently from the disc-shaped profile 41 at the proximal end and differs, for example, in terms of slit height or the slit height variation scale (of the star-shaped profile 40). Unlike the disc-shaped profile 41 at the proximal end, the disc-shaped profile 41 here is integrally formed with the core (around it), just as in… Figure 3b As schematically shown in the lower part. However, the disc-shaped profile 41 may include a (surrounding) disc assembly having a plurality of disc plates 46.

[0153] High braking torque can be obtained by the second coil 262 through the second brake gap 5b, especially at low speeds of the housing 13. A relatively strong magnetic field can be transmitted from the core 21 to the housing 13 by the first coil 261 through the first brake gap 5a in the region of the disc-shaped profile 41 at high speeds, because the gap height 41b is significantly smaller than the radial clearance 11c within the brake gap 5b region. This results in high torque, achievable especially at higher speeds. Thus, high and finely adjustable torque can be provided throughout the entire speed range by selectively controlling the two coils 261 and 262 individually.

[0154] The axial width 11e of the second brake slit 5b and the width 41e of the first brake slit 5a are approximately equal (+ / -25%) and are each shorter than the axial width of the third brake slit 5c. Overall, a very compact structure is achieved.

[0155] Shell 13 in Figure 3a The knob 23 is surrounded by a cover 49 shaped like a knob 23. The knob 23 is designed to be at least partially transparent so that it can be illuminated by a light-emitting element 18 in the form of an LED. The illumination can be controlled depending on the situation or independently of the situation. This embodiment is primarily intended for use in steering mechanisms for computer games, but it can also be advantageously used in vehicles.

[0156] At the front end, the closed cavity 110 within the housing 13 is sealed by the front cover 14, through which the braking component 2 passes. A seal 38 is used for sealing. At the rear or distal end, the cavity 110 is initially defined by an elastic diaphragm 31, to which a snap-action plate-like clicker 29 is designed to engage outwards.

[0157] The second coil 262, or its core material, is also designed as a reluctant magnet mechanism 305. When the reluctant magnet mechanism 305 is activated beforehand, it leaves a magnetic field even after the power supply is turned off. This magnetic field affects the medium 6 and thus maintains the braking torque. Therefore, steering wheel locking can be achieved without additional power consumption, for example. Parked vehicles will therefore consume as little power as possible, preferably none at all, because otherwise the battery may be discharged (not only in vehicles with internal combustion engines, but also in electric vehicles). Steering wheel locking should therefore also apply a high locking torque without current. This can be achieved using a reluctant magnet mechanism.

[0158] Figure 3b A slightly different illustration is shown, featuring a braking mechanism 1, which differs from the one described here. Figure 3a Remove the covering layer 49 or knob 23.

[0159] Figure 3a and Figure 3b The main difference between them is that, Figure 3bA first brake slit 5a with a disc-shaped profile 41 is provided at the far end of the housing 13, while a second brake slit 5b is provided at the near end of the housing 13.

[0160] In this design, for example, a support member for supporting the housing 13 relative to the braking component 2 may be provided outside the cavity 110 between the seal 38 and the sensor device 70. However, it is also possible that the support is achieved at one end solely through the seal 38, and at the other distal end solely through the disc-shaped profile 41.

[0161] The disc-shaped profile 41 can be designed to be integrated with the core (surrounding), just like in... Figure 3b As schematically shown in the lower portion. Or the disc-shaped profile 41 includes a (surrounding) disc assembly having a plurality of disc plates 46, as in, for example, in Figure 3b As shown in the upper part. The disc-shaped profile is also fitted onto the core as a solid, independent piece, that is, it is actually composed of a single disc-shaped plate with a correspondingly thicker thickness.

[0162] Figure 3b For example, several magnetic field lines 8 of the first coil 261 and the second coil 262 are drawn, indicating the general axial direction of the magnetic field lines within the core 21 and the housing 13. It can also be seen that the magnetic field lines 8 (approximately) pass radially through the brake gaps 5a and 5b, respectively. Higher torque is generated at higher speeds in brake gap 5a, while higher torque is generated at lower speeds in brake gap 5b. Each magnetic field closes in the central region via a radial transition at (approximately) the third brake gap 5c. At brake gap 5c, a narrow gap actually exists, similar to the first brake gap, where a cylindrical disc profile 41 is used.

[0163] The magnetic field sensor 72 is mounted on the sensor circuit board 79 and can be contacted via the pin-shaped contact 79a. This also supplies current to the coil 26.

[0164] An inner braking component 2, preferably made of a material with poor magnetic permeability or non-magnetic permeability, is formed at least in the areas of the sensor device 70 and the magnetic field sensor 72 to ensure that the orientation and strength of the magnetic field of the magnetic ring unit 71 within the shaft 12 or the first braking component 2 are detected with minimal interference. The sensor device 70 is housed there, in particular, in a protected manner (waterproof and dustproof).

[0165] exist Figure 3b O-ring 39 can be seen, which is relative to the housing 13 and sealing cover 14.

[0166] The third braking gap 5c is formed on the annular profile 61. The annular profile 61 can be a separate ring fitted onto the core 21 or mounted on it, or the annular profile 61 and the core 21 can be integrally formed. The annular profile 61 is always magnetically coupled to the core 21.

[0167] Figure 3b An alternative embodiment is also shown schematically in the upper half, in which a fourth brake slit 5d is integrated. The fourth brake slit 5d can, for example, be provided by the annular profile 61 as two brake slits 5c, 5d separated from each other. For example, it can include two magnetically permeable annular elements separated from each other by a less magnetically permeable intermediate element or annular element 61a. Thus, two axially separated brake slits 5c and 5d are formed. In other designs, the coils 261, 262 and the brake slits 5c, 5d can also be arranged further apart, resulting in two mutually distant magnetic loops.

[0168] The structure with three brake gaps and a centrally located brake gap 5c for two coils 261 and 262 enables a very compact structure.

[0169] like Figure 3a or Figure 3b The illustrated structure provides an advantageous design. The second coil 262, via the roller 11, allows for a strong braking torque in the second brake slit portion 5b, especially at low speeds or when stationary. The first coil 261 allows for a high braking torque over a small slit height range within the first brake slit portion 5a at higher speeds.

[0170] If braking of the rotational motion is required to provide a stop, the first coil 261 at the first brake gap 5a allows for stronger braking at higher speeds than the second coil 262 at the second brake gap 5b. At relatively low transition speeds, the braking torque generated by the second coil 262 at the second brake gap 5b is greater than the braking torque generated at the first brake gap 5a at the same speed. By using targeted combinations of brake gaps 5a and 5b, optimal conditions can be adjusted for different speeds.

[0171] The cavity 110 contains a magnetorheological medium containing magnetorheological particles 19. A gap 5 is provided between the braking components 2 and 3 within the cavity 110. The three braking gaps 5a, 5b, and 5c are formed at the gap 5. The cavity 110 is at least partially filled with a magnetorheological medium 6. This medium is preferably a magnetorheological fluid, which, for example, contains oil as a carrier liquid, and the oil contains ferromagnetic particles 19. Ethylene glycol, fats, water, and viscous substances can also be used as carrier media, but are not limited to these. The carrier medium can also be gaseous, or a carrier medium can be omitted (vacuum). In this case, only the particles 19 that are susceptible to magnetic field influence are filled into the cavity 110.

[0172] The ferromagnetic particles 19 are preferably carbonyl iron powder, wherein the size distribution of the particles depends on the specific application. A particle size distribution between 1 and 10 micrometers is particularly preferred, but larger particles of 20, 30, 40, and 50 micrometers are also possible. Depending on the application conditions, the particle size can also be significantly increased, even entering the millimeter range (particle spheres). The particles may also have special coatings / shells (titanium coating, ceramic shell, carbon shell, etc.) to better withstand the high pressure loads that may occur depending on the application. The magnetorheological particles can be manufactured not only from carbonyl iron powder (pure iron) but also, for example, from special iron (hardened steel) for the application.

[0173] It is possible to fill, for example, slits 5 or cavities 110 with particles that can be affected by a magnetic field, where air or an inert gas may be added. When using, for example, only air or other gases, various solids can be mixed to improve certain properties. For example, graphite powder can be mixed to reduce friction between carbonyl iron particles because graphite exhibits lubricating properties. The particles can be coated with PTFE in particular. Coating with PTFE or a similar coating can prevent particle agglomeration and the formation of larger lumps. Such larger lumps are not easily broken down or, in some cases, do not even break down. Alternatively, disc-shaped or rolling elements can also be coated with PTFE to reduce friction. In the case of using MRF without oil or other fluids as a carrier medium, water must be ensured to condense in the braking chamber (MR space or MRF space). For example, silica gel (called silica gel) or other desiccants can be mixed in for this purpose, which absorbs water and thus removes moisture from the environment.

[0174] In all designs, improvements, and embodiments, it is preferable to use powder without a carrier liquid. Thus, up to approximately 80% carbonyl iron (iron powder) can be used, which significantly increases the braking torque, doubling the braking torque when other design parameters are adapted (e.g., the field strength per particle should remain approximately constant in this case, as in a magnetorheological fluid (MRF), i.e., the field strength in the braking gap or effective gap should be twice as high when changing from, for example, LORD MRF 140 (40% carbonyl iron along with, for example, oil as a carrier liquid) to 80% carbonyl iron powder (without carrier liquid)). We refer here to the magnetic field strength within the gap as values ​​above 200 kA / m up to 1000 kA / m (1000000 A / m). Another advantage of using powder as a medium within the effective gap is that very small deposits inevitably occur, and iron powder not in the MR liquid is attracted to the magnetic field gradient (the force always acts towards the stronger magnetic field acting on the magnetized particles, and the carrier medium is "displaced"), thus achieving high particle concentration. This promises to achieve maximum particle concentration. This improves the reproducibility of torque (similar braking torques always occur under the same current).

[0175] In all designs, it is particularly preferred that the magnetically polarizable particles (a significant portion) comprise non-circular particles (non-spherical particles), where the ratio of the maximum diameter to the maximum lateral extension perpendicular to it is greater than 1.25 or 1.5. This ratio can also be formed as the ratio of the maximum longitudinal extension to the maximum lateral extension, wherein the longitudinal and lateral extensions perpendicular to each other are measured in particular.

[0176] The use of non-circular particles is particularly advantageous because they allow for effective tilting structures, as the distinct non-circular portions of the particles clamp or wedge against each other.

[0177] It is also possible and preferred that the ratio of the maximum diameter to the maximum lateral extension dimension perpendicular to it is 1.75 or 2.0 or greater.

[0178] Preferably, at least one portion of the magnetically polarizable particles is designed to clamp or wedge together in a planar manner under the influence of a magnetic field. This is possible, for example, in the case of particles that are locally angular or, for example, generally triangular or polygonal. Thus, two (or more) appropriately designed particles clamp together and can cause very effective particle agglomeration and clamping and braking of two braking or clutch components.

[0179] Preferably, at least one portion of the magnetically polarizable particles is designed to clamp or wedge together at two or more spaced-apart sites under the influence of a magnetic field. Such non-circularly shaped particles allow for a very effective increase in braking force or torque because, unlike spherical particles, they do not contact at only one site or a small angular area, but rather at multiple sites or in a planar manner.

[0180] Preferably, at least one portion of the magnetically polarizable particle has at least one groove. This inwardly raised groove allows for particularly effective wedging with portions of other particles.

[0181] Preferably, the surface wall of at least one adjacent brake gap of at least one clutch or brake component is designed to be at least partially rough or (locally) uneven. It is also possible that a considerable portion of the particle or magnetically polarizable particle has protrusions or bumps and / or recesses on its outer surface, either ordered or disordered. This can reinforce the tilting along with the particle. For example, at least one surface may have protrusions and / or recesses in the form of sharp or rounded dimples, like those found on a golf ball. It is also possible that the surface has a sharp or rounded serrated profile. The relative height of (at least some of these) protrusions or recesses is preferably at least 5% or 10% of the minimum diameter of the magnetically polarizable particle.

[0182] It has been shown that high magnetic field strength can be used to achieve particularly effective tilting and clamping of certain particles. Therefore, a magnetic field strength greater than 150 kA / m, 250 kA / m, or 500 kA / m is preferably generated within the braking gap. In particular, a magnetic field strength greater than 500 kA / m, 750 kA / m, or 1000 kA / m can be generated or will be generated therein within the braking gap, preferably at least one of the braking gap sections.

[0183] When using only powder without a liquid carrier medium, different seal types can be selected, and the basic friction is thus reduced. Therefore, the seal does not need to be strongly pressed against the surface, as it is not for sealing the liquid, but only the particles. However, non-contact shaft seals such as labyrinth seals can also be used. This type of seal is placed on only one of the two rotating parts. Furthermore, temperature correlation is reduced or almost eliminated. The viscosity of a fluid carrier medium changes with varying temperatures, while carbonyl iron powder hardly changes its properties over a wide temperature range (up to the Curie temperature). Temperature-induced volume changes are also negligible in the case of powder, because particles can redistribute themselves when some particles undergo volume changes.

[0184] The maximum volume fraction of carbonyl iron particles is also higher in powder form (approximately 74%) than in MRF with oil, for example, as a carrier medium.

[0185] Magnetorheological particles 19 form chains under magnetic field loading, such as in... Figure 3c As shown schematically on the left side. This results in a wedge effect, which leads to a significant increase in braking torque at low and medium speeds.

[0186] To illustrate the effect in more detail, reference is made to the accompanying drawings in the applicant’s national application WO 2018 / 215350 A1, the interpretation of which is fully incorporated into the disclosure of this application in an appropriate manner.

[0187] Figure 3c Schematic cross-sections of brake gaps 5a, 5b, and 5c are shown in principle. Figure 3c The right side of the image shows a cross-section of the first or third brake slot 5a, 5c in the region of the disc profile 41. The disc profile 41 provides a disc body 42, which is mounted to the core 21 or formed thereon as a one-piece annular flange. A gap height 41b exists radially outward between the outer profile of the disc profile 41 and the inner circumferential surface of the housing 13, which is significantly smaller than, and optionally significantly smaller than, the radial clearance 11c in the second brake slot 5b. The disc body 42 may be solid or may be designed as a disc assembly 44 including multiple disc plates 46. The first and third brake slots 5a, 5c may, in principle, have the same or similar cross-sections.

[0188] Exemplary only Figure 3c The roller 11 is drawn with dashed lines in the right-hand portion to indicate its distinction. A smaller gap height 41b is clearly visible within the disc-shaped body 42. This allows for the acquisition and transmission of strong braking torque and a high magnetic field strength. The desired magnetic field strength and braking effect can be adjusted independently via other coils in the second braking gap 5b. The two magnetic fields are closed through the third braking gap 5c.

[0189] exist Figure 3c The left side of the image shows a cross-section of another embodiment of the brake slit portion. The brake slit portion has a disc-shaped profile 41 designed as a star-shaped profile 40. The star-shaped profile 40 has a non-circular circumferential surface. This results in a brake slit portion with a slit height 40c that is variable within the circumference. This can also produce a wedge effect, and especially at low speeds, regulate high torque. Radially outward (or inward) protruding elements can be referred to as magnetic field concentrators 80, which locally concentrate the magnetic field. The star-shaped profile 40 can also be designed as a disc assembly 44 and include multiple (e.g., star-shaped) disc plates 46.

[0190] A star-shaped profile can also be formed axially. This means that the slit height can vary axially. Thus, the magnetic field can be concentrated axially at sites with smaller slit heights and reduced in higher slits. A combination of radial and axial, or / and inclined star-shaped profiles, is also conceivable.

[0191] In particular, this design is applicable to the second brake gap 5b as a replacement for the (second) brake gap (5b) with rollers.

[0192] Figure 4a The sensor device 70 is shown in detail. The first braking component 2 and the second braking component 3, which is designed as a housing 13, are only shown (dashed lines). The sensor device 70 is magnetically decoupled from the rotatable second braking component by a decoupling mechanism 78. The shielding mechanism 75 here consists of three shields 76, which reduce the leakage magnetic field 8 of the electric coil 26. The shielding mechanism 75 may also consist of only a plurality of canisters or a canister and a disc, which are interconnected.

[0193] In addition, an isolation unit 77 for magnetic isolation is provided. A magnetic ring unit 71 is used to measure the orientation or rotation angle of the magnetorheological braking mechanism 1. A magnetic field sensor 72 is arranged within the first braking component 2, which is not designed to be magnetic, in this area. For example, a small relative axial displacement caused by the operation of a throttle plate can be used to detect the operation of the operating button 101. Figure 4b As shown. The rotation angle and orientation of the magnetic field lines, indicated by the arrows, can be detected by the magnetic field sensor 72.

[0194] This axial displacement causes the sensor device 70 to receive signal 68 according to... Figure 4b The diagram shows the changes. Figure 4b The diagram shows the variation curve of the amplitude 69 of the signal 68 detected by the magnetic field sensor 72 in relation to the relative axial displacement of the braking components 2 and 3. The axial displacement of the magnetic field sensor 72 relative to the magnetic ring unit 71 causes a change in the amplitude 69 of the detected signal 68. The axial displacement or depressurization of the operating button 101 can therefore be detected.

[0195] Using the same sensor 72, the rotation angle can also be measured, where the direction of the magnetic field 8 (arrow shown) is determined to measure the rotation angle. This intensity determines the axial position. Therefore, the operation of the button or throttle 29 can be inferred from the change in signal 68. This is advantageous because a single (multidimensional) Hall sensor can be used to determine both the angular and axial positions.

[0196] Figure 6 Two coils 261 and 262 with different designs are shown schematically, where the number of windings may differ. The diameter, type, shape, and material of the metal wires 263 and 264 may also differ. The dimensions and shapes of coils 261 and 262 may be the same (shown by solid lines) or different, so the second coil 262 may, for example, have a smaller cross-section than that shown by dashed lines. This allows for different characteristics to be tuned at the magnetic circuit. One magnetic circuit may be designed for faster response speeds and / or higher braking torque, while another may be designed for better braking performance and / or higher energy efficiency. Dramatically different performance combinations can be obtained. The materials at the brake slits can also be different.

[0197] Figure 7a A schematic cross-section of another braking mechanism 1 is shown, in which a first braking component 2 is housed on a support 4 that serves as a shaft 12. This design also includes three braking slits 5a, 5b, and 5c, with disc-shaped profiles 41 formed at the first and second braking slits 5a and 5b, respectively.

[0198] An internal reservoir 32 for magnetorheological particles can be provided to ensure an adequate supply of magnetorheological particles to the braking gap. In particular, carbonyl iron particles are attracted from the surrounding environment and concentrated in the magnetic field transition region.

[0199] exist Figure 7a In the middle, cover 14 is installed at the front end (left end), and cover 15 is installed at the rear end.

[0200] The disc-shaped body 41 is designed to be integrated with the core 21, but it can also be designed as a disc assembly 44 with multiple disc-shaped plates 46.

[0201] The outer diameter of the housing 13 and consequently the braking circuit here is between 80 mm and 130 mm. In this example, it is 125 mm. The correspondingly large diameter allows for a high torque.

[0202] A cable through-hole 12a is formed on the hollow shaft 12, through which cables for supplying power to the two coils 261, 262 are passed. A (separate) core 21 is housed within the internal components. On the core 21, the two coils 261, 262 are wound onto a coil holder 26b. An annular profile 61 for the third braking slit portion 5c is accommodated or formed between the two coils 261, 262. In a simplified design, the annular profile 61 is mounted as a separate piece on the core 21, providing a narrow slit between the outer surface of the annular profile 61 and the inner circumferential surface of the housing 13, such as... Figure 7a As shown on the upper side. The annular contour 61 can also be integrally formed with the core, see... Figure 7a The lower side. The third braking gap 5c is used to close the two magnetic fields of the two electric coils 261 and 262.

[0203] The magnetic field of the first coil 261 extends substantially radially through the first brake gap 5a and the third brake gap 5c, and axially through the core 21 and the housing 13. The magnetic field of the second coil 262 extends substantially radially through the second brake gap 5b and the third brake gap 5c, and axially through the core 21 and the housing 13. The two coils 261 and 262 are wound and energized such that their magnetic fields extend in the same direction within the region of the third brake gap 5c, as if... Figure 3b As shown in the text.

[0204] Overall, a braking mechanism 1 that can be manufactured at very low cost is provided, wherein at least one support can be saved if necessary by means of a "support" of the disc-shaped profile 41, thereby also reducing the structural height. Very low basic friction is achieved. Manufacturing is simple and low-cost due to the use of fewer parts. The fewer parts also improve error requirements by avoiding error chains.

[0205] The braking torque can be adjusted independently using two coils 261 and 262.

[0206] Figure 7b Shown in perspective Figure 7a Braking mechanism 1.

[0207] Figure 8A schematic cross-section of another braking mechanism 1 is shown, which is equipped with a drive unit 307 designed to drive a motor 90. The drive motor 90 can actively rotate the steering unit 301. The drive motor 90 is integrated into the braking mechanism 1 and is designed, for example, as a BLDC motor (brushless DC motor). Here, the drive motor 90 includes a core 91 and windings 92, as well as one or more permanent magnets 93 and a (static) support 94. However, embodiments without permanent magnets (e.g., electrically excited motors) are also feasible.

[0208] The support member 94 is fixed here and fixedly connected to the support 4, thus generating torque (Actio = Reactio) during braking and active drive. Here, the aforementioned components of the drive motor 90 are arranged radially and axially within the outer periphery defined by the brake gaps 5a, 5b, and 5c. The MRF brake can be said to be constructed radially around the drive motor 90, thereby significantly saving structural space. This is particularly advantageous in the case of the steering system 1 used in autonomous vehicles, where it is typically desired that the steering wheel can be moved forward by 300 mm by the person sitting in the driver's seat so that the person can, for example, work on a laptop while the vehicle is autonomously driven. For such a large travel, the cockpit typically does not provide sufficient structural space. With the invention shown here, such structural space is provided.

[0209] Figure 9 The circuitry for rapid control of coil 26 is schematically illustrated. Coil 26 (magnetic coil) is controlled here via circuit H. This is in... Figure 9 This is indicated solely by a switch. A voltage source 35a, with a lower voltage of, for example, 12V, provides the voltage for normal operation or continuous operation. For voltage peaks, a voltage source 35b, with a higher voltage of, for example, 18V or 24V, is switched on. This temporarily disconnects the lower voltage source 35a. After the maximum current is reached, the higher voltage source 35b is disconnected from the circuit and the coil 26, and the lower voltage source 35a is switched on again. The switch can be any electrical component, especially those capable of millisecond-level switching.

[0210] As a result, the current in coil 26 reaches the desired value more quickly. In specific cases, the desired current intensity is reached within 10 ms instead of 40 ms. The switching between voltages can be achieved through a circuit.

[0211] Figure 10Two curves illustrating the resulting braking torque are shown schematically, with the generated braking torque (normalized and therefore dimensionless here) plotted above the electrical input power (normalized and therefore dimensionless here). The curve on the left is for a BLDC motor (brushless DC motor), and the curve on the right is for a magnetorheological braking mechanism. It can be seen that the same braking torque from the electric motor requires significantly more power than from the magnetorheological braking mechanism. For a braking torque of "14", the electric motor requires more than the normalized power of "130", while the magnetorheological braking mechanism requires less than "0.3" (significantly) lower power. The power consumption ratio is greater than 100:1 and is approximately 500:1 in this case.

[0212] Magnetorheological clutches and brakes typically offer advantages such as requiring only a small current for engagement or damping motion, gentle operation, minimal heat generation, and rapid response (ms). The low current requirement is particularly advantageous in the case of battery-powered components in electric vehicles, where the power consumption of all components is directly reflected in the vehicle's travel distance. However, power consumption is also a concern in vehicles with internal combustion engines or general electrical systems.

[0213] This system requires significantly less current than control achieved solely by an electric motor. Currently, electric vehicles typically achieve approximately 6 kilometers of range per 1 kWh battery, with each kWh battery costing around €230 and adding approximately 6 kilograms of extra weight. Even if these figures change in the future, energy demand will continue to play a crucial role. Figure 11 The diagram shows the braking torque curves of the magnetorheological braking mechanism 1 for two different current intensities over time. Here, the dashed curve in the upper half of the figure represents the conventional curve, where the current intensity is directly increased to the desired current intensity.

[0214] Here, the current intensity is increased from 0 Amperes to 2 Amperes at 0.1 seconds. The resulting braking torque curve or engagement strength curve is... Figure 11 The lower half is shown by a dashed line. The transferable braking torque increases from a starting point of 0.1 seconds in the dashed curve to a reading of approximately 1.25 within approximately 25 milliseconds (0.125 seconds) (normalized to, for example, intermediate or standard units), and asymptotically (approximately) reaches a regulated limit of approximately 1.5 after approximately 75 milliseconds (0.175 seconds).

[0215] At the start of the clutch engagement or braking / damping process, the current intensity is tripled to, for example, 6 amps in this case, as shown by the solid line. The braking torque increases significantly and reaches a final value of 1.5 after approximately 10 milliseconds. Here, the "current surge" with a higher current intensity is initiated only about 10 ms. Subsequently, the current intensity is reduced to 2 amps, as shown by the solid line above. By briefly increasing the current intensity (current surge), a significantly faster adjustment (for use) of the clutch torque, damping torque, or braking torque can be achieved. This is extremely advantageous in many ways, as a rapid stop and direct tactile feedback can be experienced. A major advantage of this structure is that no external cables, sensors, or electronics are required. Therefore, a high IP rating can be achieved in all designs. In principle, all are installed after the baffle is mounted.

[0216] The coil is preferably completely separated from the space containing the magnetorheological medium, especially by filler.

[0217] Axial displacement can be achieved in the preferred design, particularly the internal movement of the liquid volume. Sufficient space is preferably provided between the cap and the disc profile so that the medium (or liquid) or carbonyl group located therein is not sealed (otherwise this would result in high axial adjustment forces). This provides an additional MRF reservoir from which particles can replenish the flow into the area of ​​the disc profile or rollers. That is, magnetic particles always flow towards the stronger field because they are attracted by the magnetic field gradient.

[0218] The seal preferably extends on the shaft. Rotational motion (over 100,000 revolutions is possible) and linear motion for the key may occur. Therefore, the seal is not worn and forms a channel, resulting in low friction and low leakage (oil carrying) over its service life. A corresponding material pair with a hardened working surface is preferred.

[0219] The first brake slit portion 5a is preferably equipped with a disc-shaped profile. The second brake slit portion 5b is particularly equipped with rollers, especially rollers. Rollers, especially rollers with a circular inner ring, can achieve high static torque. The disc-shaped profile allows for good magnetic field transmission and high torque at high speeds.

[0220] This combined solution, also known as a hybrid solution, integrates the advantages of both. The axial transition portion of the magnetic field has a smaller transition area than in the prior art, resulting in a smaller braking torque. Furthermore, the axial magnetic field transition has a smaller distance (radius) and therefore already generates a smaller torque. The radially arranged brake slit 5a with a disc-shaped profile also has a larger diameter compared to this, thus generating a larger torque under the same force. Additionally, the area is larger because a larger circumference defines a larger area. When the width of the profile disc is greater than 1 / 6 of its diameter, the transmittable braking torque at the (considerable) radial brake slit is already greater than the maximum transmittable braking torque on the axial surface! Finally, the magnetic signal is smaller due to the smaller slit height at the disc-shaped profile. All of these contribute to a higher braking torque even at higher speeds.

[0221] Volume compensation for the pressing function can be provided via a membrane at the end of the housing. A click element, such as a snap-action piece (metal spring), is located behind the membrane. It provides a tactilely perceptible pressure point. Furthermore, one hears a click when the pressure point is reached, and the snap-action piece pushes the entire button or housing back to its initial position (similar to a mouse button in a computer mouse).

[0222] Therefore, the diaphragm seals the MRF cavity. The volume behind the diaphragm is compensated for during pressing. In the normal position, the quick-acting plate has a raised shape. If the button is moved axially, the stator of the braking mechanism presses against the diaphragm and the quick-acting plate. The quick-acting plate is thus flattened.

[0223] As a transparent material, it can be reused as glass or PMMA (plexiglass). The advantage of PMMA is that it can be used with milky white glass, which refracts light internally and thus illuminates the entire surface evenly. One or more LEDs, possibly of different colors, can be used for illumination.

[0224] In all design schemes, the outer braking component can also be designed to be non-rotatable while the inner braking component can be rotatable. In this case, the electrical contact of the coil via the wire must be achieved through the outer braking component, or for example, through a sliding contact.

[0225] Using the invention presented herein, the desired operating range of the steering device 100 can be divided into multiple sub-ranges. A first sub-range is provided by the drive unit 307, providing, for example, an active driving torque between 0 and 8 Newton-meters. A second sub-range is provided by a first brake slit 5a, providing, for example, a braking torque between 0 and 5 Newton-meters. A third sub-range is provided by a second brake slit 5b, providing, for example, a braking torque between 0 and 25 Newton-meters. Here, a high adjustment quality is achieved for the first sub-range due to the disc-shaped profile 41 within the first brake slit 5a. Because this sub-range is particularly important for steering accuracy, the high adjustment quality advantageously influences steering behavior.

[0226] The steering device 100 proposed here also has the following advantages: the required active torque (driving torque) can be obtained by a compact and flexible electric motor with high adjustment quality and low power consumption (higher efficiency in the partial load range). The required low passive torque (braking torque, for example, reaching 8 Nm) is obtained here with a small basic torque and high adjustment quality while maintaining low power consumption through the first brake slit 5a. The required higher passive torque (braking torque, for example, reaching 25 Nm) is also obtained here with a small basic torque and normal adjustment quality while maintaining low power consumption through the second brake slit 5b. This results in triple redundancy.

[0227] Simultaneously, it can affect steering movements without noise or bumps. Furthermore, braking mechanism 1 can brake its driving torque in the event of a malfunction of drive unit 307. Additionally, the braking mechanism can smooth or level the motor curve (fluctuating torque within the rotation angle range). Moreover, the current consumed by braking mechanism 1 is significantly less than that of a motor used to generate a similar braking torque.

[0228] The proposed steering mechanism can also be used in combination with an onboard computer, display instrument, or head-up display as a game controller, driving simulator, or flight simulator. When the vehicle is parked (e.g., during charging in the case of an electric vehicle) or when the car is in self-driving mode, the user can use the steering mechanism as an input device for computer games. Haptic feedback is preferred when switching from game mode to real driving operation.

[0229] Certain parameters of the steering system can also be adjusted, configured, or stored within the system limits in a customer-specific manner via the onboard computer or other input devices (personalization). Individual settings can be retrieved via key recognition, smartphone or smart device communication, driver recognition (image recognition; facial recognition), gesture control, voice control, data analysis, or manual input.

[0230] List of reference numerals

[0231] 1. Magnetorheological braking mechanism

[0232] 2,3 Braking components

[0233] 4 supports

[0234] 5 gaps

[0235] 5a Brake gap for 41

[0236] 5b Braking analysis unit for 11

[0237] 5c for the brake gap of 61

[0238] 5d Brake Gap

[0239] 6. Medium

[0240] 8. Magnetic field, field

[0241] 11 Rollers

[0242] 11b 5b gap height

[0243] Radial gap at 11c 5b

[0244] The diameter of 11d 11

[0245] 11e 11 axial width

[0246] 11F bracket

[0247] 12 axis lines

[0248] 12a Cable Through Hole

[0249] 13. Shell

[0250] 14. To close, to cover

[0251] 15. Closed, covered

[0252] 16 sales

[0253] 18 Light-emitting components

[0254] 19 Magnetic Particles

[0255] 20 Rotation axis, axial direction

[0256] 21 core

[0257] 22 hubs

[0258] 23 Knobs

[0259] 26 coils

[0260] 26b Coil Holder

[0261] 26e Axial width

[0262] 28 Packing

[0263] 29 Speed-motion film

[0264] 29a Guiding Mechanism

[0265] 29b volume

[0266] 31 membrane

[0267] 32 storage units

[0268] 35A 12V voltage source

[0269] 35b 18V voltage source

[0270] 38 Seals

[0271] 39 O-rings

[0272] 40 Star-shaped outline

[0273] 40c gap height

[0274] 41. Disc-shaped outline

[0275] 41a One-piece annular flange

[0276] 41b 5a gap height

[0277] axial width of 41e 5a

[0278] 42. Ring-shaped bodies, disk-shaped bodies

[0279] 42a Container

[0280] 43 User Interface

[0281] 44 disk group

[0282] 45 Cable

[0283] 46 Disc-shaped plate

[0284] 47 The resulting outer contour

[0285] 48 Filler screws

[0286] 49. Coating

[0287] 50 brackets

[0288] 51 Nut

[0289] 61. Circular Profile

[0290] 68 signal

[0291] 69 Amplitude

[0292] 70 Sensor Device

[0293] 71 Magnetic Ring Unit

[0294] 72 Magnetic Field Sensor

[0295] 75 Shielding mechanism

[0296] 76 Shielding

[0297] 77 dividing units

[0298] 78 Decoupling mechanism

[0299] 79 Sensor Circuit Board

[0300] 79a Needle-type contact

[0301] 80 Magnetic field concentrator

[0302] 90 drive motor

[0303] 91 cores

[0304] 92 windings

[0305] 93 Permanent Magnets

[0306] 94 Support components

[0307] 100 Steering mechanism

[0308] 101 Operation Buttons

[0309] 102 Operating roller

[0310] 110 Closed cavity

[0311] 200 Instrument Components

[0312] 261 coil

[0313] 262 coils

[0314] 263 Metal Wire

[0315] 264 Metal Wire

[0316] 301 Steering Unit

[0317] 302 Steering Controller

[0318] 303 Actuator Device

[0319] 304 Driver Assistance System

[0320] 305 coercive mechanism

[0321] 306 Safety Devices

[0322] 307 drive unit

[0323] 311 Steering Axle

Claims

1. A steering device (100) for controlling a vehicle by means of a movable steering unit (301), wherein, The movement of the steering unit (301) can be braked by at least one magnetorheological braking mechanism (1), wherein the braking mechanism (1) includes a fixed support (4) and at least two braking components (2, 3), wherein at least one of the two braking components (2, 3) is rotatable by the steering unit (301), wherein at least another of the two braking components (2, 3) is non-rotatably connected to the support (4), and wherein the two braking components (2, 3) are rotatable relative to each other about a rotation axis (20), wherein the first braking component (2) extends along the rotation axis (20) and includes a core (21) made of a magnetically conductive material, and wherein the second braking component (3) includes a hollow shell (13) extending around the first braking component (2), wherein at least one surrounding slit (5) at least partially filled with a magnetorheological medium (6) is formed between the first braking component (2) and the second braking component (3), characterized in that the slit (5) includes at least two different Brake gaps (5a, 5b), and a disc-shaped profile (41) is formed in the first brake gap (5a) between the housing (13) and the core (21), and a disc-shaped profile (41) different from that in the first brake gap (5a) is formed in the second brake gap (5b) between the housing (13) and the core (21), wherein the steering device (100) includes at least one steering controller (302) for controlling the braking mechanism (1) based on at least one of the position of the steering unit (301), the motion parameters of the steering unit (301), and the operating state of the vehicle, wherein the at least two different brake gaps (5a, 5b) can be individually controlled by the steering controller (302), and wherein the steering controller (302) is adapted and designed to select at least one of the at least two different brake gaps (5a, 5b) to brake the movement of the steering unit (301) based on the magnitude of the braking torque to be adjusted.

2. The steering device (100) according to claim 1, wherein, At least one third brake gap (5c) is provided axially between the first brake gap (5a) and the second brake gap (5b), wherein a first electric coil (261) is assigned to the first brake gap (5a) and a separately controllable second electric coil (262) is assigned to the second brake gap (5b).

3. The steering device (100) according to claim 1 or 2, wherein the steering device (100) includes at least one drive device (307) for generating driving torque for active movement of the steering unit (301), wherein, The drive unit (307) includes at least one electric motor arranged radially within the outer contour defined by the slit (5).

4. The steering device (100) according to claim 1, wherein the steering device (100) includes an actuator mechanism (303) for converting the steering motion achieved by the steering unit (301) into vehicle motion, wherein, The steering unit (301) and the actuator mechanism (303) are electrically and / or electromagnetically connected only, thereby providing so-called steer-by-wire.

5. The steering device (100) according to claim 1, wherein, The braking mechanism (1) has a braking torque under the effective influence of the magnetorheological medium (6) and a basic torque under the ineffective influence of the magnetorheological medium (6), wherein the basic torque is at least 50 times smaller than the maximum available braking torque.

6. The steering device (100) according to claim 1, wherein, A first coil (261) is assigned to the first brake gap (5a) and a separately controllable second coil (262) is assigned to the second brake gap (5b).

7. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to combine at least two of the brake gaps (5a, 5b) according to the magnitude of the braking torque to be adjusted, thereby braking the movement of the steering unit (301).

8. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to generate a braking torque for braking the steering unit (301) at least at the first brake gap (5a) when the vehicle speed is above the limit value.

9. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to lock the mobility of the steering unit (301) and generate the required braking torque with the second brake gap (5b) and / or with a combination of at least two different brake gaps (5a, 5b).

10. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to generate an end stop for the mobility of the steering unit (301) with at least a second brake gap (5b) and / or a combination consisting of at least two different brake gaps (5a, 5b).

11. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to brake or even lock the activity of the steering unit (301) in accordance with the driving assistance system (304), thereby preventing dangerous steering movements, and for this purpose selects and controls at least one of the at least two different brake gaps (5a, 5b).

12. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to take user characteristics into account when adjusting the braking torque.

13. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to adjust the braking torque based on where the steering unit (301) is held.

14. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to generate tactile feedback at the steering unit (301) having a prescribed braking torque sequence.

15. The steering device (100) according to claim 1, wherein, The steering controller (302) is adapted and designed to identify user behavior using at least one machine learning algorithm and take into account the adjustment of braking torque.

16. The steering device (100) according to claim 1, wherein, The magnetorheological medium (6) comprises at least one metal powder, wherein the metal powder has a volume proportion of at least 50%.

17. The steering device (100) according to claim 16, wherein, The metal powder is coated.

18. The steering device (100) according to claim 1, the steering device (100) comprising at least one coercive mechanism (305) and / or at least one permanent magnet unit, the at least one coercive mechanism (305) and / or at least one permanent magnet unit being adapted and designed to maintain braking torque with at least one of at least two different braking gaps (5a, 5b) even when no current is supplied.

19. The steering device (100) according to claim 1, the steering device (100) comprising at least one safety device (306) adapted and designed to at least partially discharge the magnetorheological medium (6) from the gap (5).

20. The steering device (100) according to claim 1, wherein, The gap (5) has a maximum diameter of less than 100 mm.

21. The steering device (100) according to claim 1, wherein the steering device (100) includes at least one drive device (307) for generating a driving torque for active movement of the steering unit (301).

22. The steering device (100) according to claim 21, wherein, The maximum braking torque of the second brake gap (5b) is at least twice the maximum driving torque of the drive device (307).

23. The steering device (100) according to claim 21 or 22, wherein, The braking mechanism (1) can provide a braking torque that is at least as large as the driving torque of the drive device (307) when the drive device (307) fails.

24. The steering device (100) according to claim 21, wherein, The steering controller (302) is adapted and designed to at least approximately balance the fluctuations in the driving torque of the drive unit (307) by adjusting the braking torque.

25. The steering device (100) according to claim 1, wherein, The disc-shaped profile (41) includes at least one star-shaped profile (40) such that a variable gap height (40c) exists around the first brake gap (5a) in the region of the star-shaped profile (40), and wherein a plurality of magnetic field concentrators (80, 81) are provided at the star-shaped profile (40) and protrude radially into the first brake gap (5a).

26. The steering device (100) according to claim 2, wherein, The first coil (261) and the second coil (262) are respectively housed between the housing (13) and the core (21) and are respectively wound around the axis of rotation (20).

27. The steering device (100) according to claim 2, wherein, The first coil (261) and the second coil (262) are configured differently, and wherein the first coil (261) and the second coil (262) differ in at least one of a set of parameters, which includes wire diameter and wire cross-section, number of windings, winding window, winding type, coil width, coil diameter and material as parameters.

28. The steering device (100) according to claim 2, wherein, The third brake gap (5c) is formed by at least one annular profile (61) arranged between the housing (13) and the core (21).

29. The steering device (100) according to claim 28, wherein, The first coil (261) is arranged axially between the first brake gap (5a) and the annular profile (61), and wherein the second coil (262) is arranged axially between the annular profile (61) and the second brake gap (5b).

30. The steering device (100) according to claim 28 or 29, wherein, The annular profile (61) is designed as a separate part, and wherein the magnetic field (8) of the first coil (261) and the magnetic field (8) of the second coil (262) extend through the annular profile (61).

31. The steering device (100) according to claim 1, wherein, Includes a sensor device (70) for detecting the relative rotation angle between the core (21) and the housing (13), and / or includes a sensor device (70) for detecting the relative axial position of the housing (13) relative to the first braking member (2).

32. The steering device (100) according to claim 1, wherein, The magnetic field strength between individual magnetically polarizable particles of the magnetorheological medium (6) is greater than 300 kA / m.

33. The steering device (100) according to claim 1, wherein, The magnetic field strength generated in the gap (5) is greater than 500 kA / m.

34. The steering device (100) according to claim 1, wherein the steering device (100) comprises at least four brake gaps (5a, 5b, 5c, 5d).

35. The steering device (100) according to claim 1, wherein the steering device (100) comprises at least two magnetorheological braking mechanisms (1).

36. The steering device (100) according to claim 5, wherein, The basic torque is at least 90 times smaller than the maximum braking torque that can be provided.

37. The steering device (100) according to claim 8, wherein, The steering controller (302) is adapted and designed to generate braking torque for braking the steering unit (301) only through the first brake gap (5a) when the vehicle speed is above the limit value.

38. The steering device (100) according to claim 9, wherein, The steering controller (302) is adapted and designed to generate the required braking torque only with the second brake gap (5b) and / or a combination of at least two different brake gaps (5a, 5b).

39. The steering device (100) according to claim 10, wherein, The steering controller (302) is adapted and designed to generate end stops for the mobility of the steering unit (301) using only the second brake gap (5b) and / or a combination of at least two different brake gaps (5a, 5b).

40. The steering device (100) according to claim 16, wherein, The metal powder has a volume ratio of at least 60%.

41. A method for operating a steering device (100) according to any one of claims 1 to 40 using a magnetorheological braking mechanism (1) having two braking components (2, 3), wherein, The two braking components (2, 3) are capable of rotating continuously relative to each other about a rotation axis (20), wherein the first braking component (2) extends along the rotation axis (20) and includes a core (21) made of a magnetically conductive material, and wherein the second braking component (3) includes a hollow shell (13) extending around the first braking component (2), wherein at least three axially spaced and surrounding braking gaps (5a, 5b, 5c) are formed between the first braking component (2) and the second braking component (3), the braking gaps (5a, 5b, 5c) being at least partially filled with a magnetorheological medium (6), characterized in that a first electric coil (261) generates a controllable magnetic field in the first braking gap (5a) and the third braking gap (5c), and independently of this, a second electric coil (262) generates a controllable magnetic field in the second braking gap (5b) and the third braking gap (5c) in order to produce braking effects of varying strengths according to the rotational speed.

42. The method according to claim 41, wherein, The first coil (261) and the second coil (262) are used to generate braking effects of different speeds.

43. The method according to claim 41 or 42, wherein, The first coil (261) and the second coil (262) are used to generate braking effects with different efficiencies.

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