Haptic operating device with magnetorheological brake mechanism

Abstract

Haptic operating device (100) with a magnetorheological brake mechanism (1) having a stationary support (4) and two brake parts (2, 3). One of the two brake parts (2, 3) is non-rotatably connected to the support (4). The two brake parts (2, 3) are continuously rotatable relative to one another about an axis of rotation (20). The first brake part (2) extends along the axis of rotation (20) and comprises a core (21) composed of magnetically permeable material. The second brake part (3) comprises a hollow-constructed housing (13) which extends around the first brake part (2). At least one annular brake gap portion which is at least partially filled with a magnetorheological medium (6) is formed between the first and second brake parts (2, 3). At least one electric coil (26) is accommodated between the housing (13) and the core (21) and is wound around the axis of rotation (20) and around the core (21). Two radially different brake gap portions (5a, 5b) are formed, wherein a disc-shaped contour (41) is formed between the housing (13) and the core (21) at the first brake gap portion (5a) and a plurality of rollers (11) are provided on the peripheral surface of the core (21) in the second brake gap portion (5b).

Description

Technical Field

[0001] The present invention relates to a tactile operating device, and more particularly to a tactile operating button, having a magnetorheological braking mechanism with a fixed support and at least two braking components that can rotate continuously relative to each other about a rotation axis. Background Technology

[0002] Tactile operation or actuation devices are particularly useful in the operation of technical devices in motor vehicles and other vehicles, for example as turntables, rotary / pressurized discs, in infotainment systems, air conditioning units (temperature, ventilation levels, distribution), as gear selectors, in navigation, in cruise control systems, in distance control, as adjustment devices, in steering systems (steer-by-wire or steering wheel in general), in two-wheel, three-wheel, or four-wheeled vehicles (such as off-road vehicles, like those from Polaris), motorboats, skis, all-terrain vehicles, in guide rods or steering systems, in chassis adjustment, in driving mode adjustment, in wiper adjustment, in window adjustment or in roof adjustment, in parking assistance, or in setting up (partial) autonomous driving, or even as a steering wheel replacement.

[0003] It can be applied in motor vehicles, airplanes, aircraft, ships, boats, and agricultural fields, such as tractors, combine harvesters, and other agricultural machinery. It can also be applied in construction machinery and machines such as forklifts, or in medical or industrial equipment.

[0004] This invention can also be used in the operation of washing machines, kitchen appliances and household appliances, radios, cameras and camcorders, high-fidelity audio equipment and televisions, smart devices, smart home devices, laptops, personal computers, smartwatches or as their input devices, in the crown wheel of a wristwatch or as the wheel of a computer mouse or as the scroll wheel of a computer mouse, in game controllers, in gaming equipment, as a knob in a keyboard or in other devices.

[0005] Magnetorheological fluids, for example, contain fine ferromagnetic particles distributed in oil, such as carbonyl iron powder. Approximately spherical or circular particles with diameters ranging from 1 µm to 10 µm, determined by manufacturing processes, are used in magnetorheological fluids, where particle size and shape are not uniform. If such a magnetorheological fluid is subjected to a magnetic field, the carbonyl iron particles of the magnetorheological fluid, or magnetorheological medium, or magnetorheological flow chain along the magnetic field lines, causing the rheological properties of the magnetorheological medium to be significantly affected by the shape and strength of the magnetic field (transmissible shear stress).

[0006] 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): https: / / www.lord.com / products-and-solutions / steer-by-wire-tactile-feedback-device. They are often used as "steer-by-wire tactile 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's operating range is 1 to 12 Nm (multiples of 12), and the 20 Nm brake's operating range is 1 to 20 Nm (multiples of 20). The relatively small working range is insufficient for many applications, as the aforementioned batch products are mainly used in large motor applications (especially those where operation is mostly done with gloves, such as industrial, agricultural machinery, forklifts, etc.).

[0007] Small motor applications, such as operating an infotainment system with a rotary / pressure disc using three fingers in a car, controlling a game controller in a game, and steering a car, all require significantly lower base torque and higher maximum torque, i.e., a significantly wider operating range. In particular, a high base torque can quickly cause fatigue or make fine adjustments difficult to the touch. However, known MRF brakes do not allow for a large operating range due to their excessively large friction area. While a smaller friction area would reduce the base torque, it would also reduce the maximum torque.

[0008] WO 2012 / 034697 A1 discloses a magnetorheological drive having two engageable components whose engagement strength can be influenced. To influence the engagement strength, a channel containing a magnetorheological medium is provided. The magnetorheological medium within the channel is affected by a magnetic field. A rotating body is provided within the channel, on which an acute-angled region containing the magnetorheological medium is formed. At least a portion of the channel can withstand the magnetic field of a magnetic field generator to selectively chain particles (magnetic) and wedge or release them with the rotating body. The magnetorheological drive can also be used in knobs for operating technical equipment. This magnetorheological drive functions effectively and allows for the transmission of considerably high forces or torques within a relatively small configuration or structural volume.

[0009] A knob or operating button is also disclosed in WO 2012 / 034697 A1, in which the actual button is mounted to be rotatable about an axis. The braking torque can be controlled by a magnetic field generated by an electric coil. If a higher braking torque is desired, a cylindrical roller can be used instead of a spherical rotating body, thus applying the magnetic field over a larger distance or area (resulting in magnetic field concentration and wedge formation through a larger area). Tactile operating devices with such rotating bodies or rollers enable satisfactory functionality and high torque for tactile operating buttons, while simultaneously exhibiting a low braking torque / basic torque ratio (e.g., less than 0.5 Nm at a maximum torque of 50 Nm) when the magnetic field is off. The ratio of maximum achievable torque to minimum torque (basic torque) is high (>100).

[0010] However, a drawback is that high maximum torque can only be achieved at low speeds of the haptic operating device. If the speed exceeds the value that depends on the individual structure, the maximum torque decreases significantly and is not always satisfactory. Summary of the Invention

[0011] The object of the present invention is therefore to provide a tactile operating device, and in particular a tactile operating button having a magnetorheological braking mechanism or a damping mechanism, thereby generating a low base torque and a relatively high maximum torque at different speeds.

[0012] The tactile operating device according to the invention can be particularly designed as a tactile operating button, knob, or rotary element. The tactile operating device has at least one magnetorheological braking mechanism with a fixed support and at least two braking components. One of the two braking components is non-rotatably connected to the support. The two braking components are continuously rotatable relative to each other about the (same) axis of rotation. The first braking component extends along the axis of rotation (axially) and includes at least a core made of a magnetically conductive material. The second braking component includes a hollow housing extending around the first braking component. Between the first and second braking components, at least one surrounding braking slot or gap is formed and is at least partially filled with a magnetorheological medium. At least one electric coil wound around the axis of rotation and (radially) surrounding the core is accommodated between the housing and the core. At least two (functionally) different braking slots are included or formed and (preferably) formed radially and / or axially or obliquely. At the first braking slot, a disc-shaped profile is formed between the housing and the core. In the second braking slot (formed between the housing and the core), a plurality of rollers are arranged on the circumferential surface of the core. These two brake gaps are preferably formed at the same gap (brake gap). These two brake gaps may also be formed at two gaps (brake gaps) that are spatially and / or structurally separated.

[0013] The tactile operating device according to the present invention has many advantages. A significant advantage of the tactile operating device of the present invention is that it includes two functionally distinct braking slits formed radially (and / or axially and / or inclined). This allows the tactile operating device to be braked in different ways at different speeds. One braking slit (determined by its function) generates higher torque at lower speeds, while the other braking slit, determined by other structural features, also generates relatively high torque at higher speeds. This results in a constant maximum torque throughout the entire speed range, which is advantageous in many applications.

[0014] The tactile operating device according to the present invention has a simple structure, uses only a few parts, and allows for easy and inexpensive manufacturing. It has low basic friction and can provide high maximum torque at different speeds, even when stationary. It is simple to manufacture and low in cost.

[0015] 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.

[0016] 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.

[0017] Rollers are used in particular as magnetic field concentrators. Because of the rollers (as magnetic field concentrators), acute angles may appear between some magnetic field lines and the radial orientation, but they usually or generally pass through the magnetic field radially. The same applies to another brake slot with a disc-shaped profile, where a three-dimensional orientation of the magnetic field lines may also appear at the radial end of the disc-shaped profile, but they are generally or generally still basically radially oriented.

[0018] In particular, a disc-shaped profile is formed in the axial region (closely connected) to the coil, or a disc-shaped body is formed between the housing and the core, and in another axial section, multiple rollers (as magnetic field concentrators) are arranged adjacent to the coil on the circumferential surface of the core. These rollers are particularly arranged in the same plane transverse to or perpendicular to the axis of rotation. Preferably, these rollers can move completely around the core. The outer surface of the core is preferably designed as cylindrical in the second braking gap.

[0019] 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 brake gap. This allows for the generation of high torque even at higher speeds and when starting from a standstill.

[0020] The magnetorheological medium, in particular, at least partially wets the first and second braking components.

[0021] (At least one) coil is preferably wound around an axis of rotation and generates a magnetic field substantially axially within the core. The coil is radially housed between the core and the housing. The coil may be wound around the core or fixed to the housing on the inside.

[0022] 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.

[0023] The disk-shaped profile is at least partially or entirely made of a (good) magnetically conductive material.

[0024] 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.

[0025] 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.

[0026] In a particularly preferred design, the disk profile has at least one disk assembly. The disk assembly is particularly composed of multiple disk plates preferably in close contact with each other. This design, for example, allows the disk plates to be processed as punching parts. Punching parts can be easily and inexpensively mass-produced. If they overlap and, for example, press against each other, a disk assembly or a disk body with a significantly thicker shape can be provided simply and inexpensively. Thus, disk plates (also called disks) and disk assemblies can be manufactured very inexpensively. Some disks can also have various different properties (e.g., due to different materials). Some disks can also be made of (sintered) magnetic materials (e.g., neodymium).

[0027] 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.

[0028] In a particularly preferred design, the disc-shaped profile generally has a cylindrical outer contour. It is also possible to design the disc-shaped profile as a star-shaped profile or to form a star-shaped profile. The star-shaped profile serving as the disc-shaped profile may have a magnetic field concentrator that (preferably) protrudes radially and / or (possibly) axially, integrally connected to or fixed to the disc-shaped profile. Thus, it is possible to provide a star-shaped profile serving as the disc-shaped profile at one braking gap. A rotating body is thus included at another braking gap.

[0029] In particular, in this design, at least one star-shaped profile can be arranged as a disc-shaped profile between the housing and the core at the brake gap. This results in a variable gap height within the brake gap area in the star-shaped profile region. In this design, the second brake gap is preferably also an axially outward brake gap.

[0030] A magnetic field concentrator is preferably formed or arranged at the star-shaped profile, which (radially) protrudes into the gap, thereby creating a second braking gap portion with a variable gap height surrounding the star-shaped profile area.

[0031] The elements used as magnetic field concentrators can protrude radially inward, radially outward, or axially from a star-shaped profile. Magnetic field concentrators can be designed in shapes such as teeth, arcs, sinuses, or trapezoids, and can be arranged in an orderly or disordered manner at varying heights.

[0032] 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.

[0033] 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.

[0034] In all designs, it is preferable that the radial clearance for a roller between the housing and the core in the second brake slot is greater than the slot height in the first brake slot (within the disc-shaped profile area). The radial clearance is here the difference between the slot height in the second brake slot and the roller diameter. Typically, the radial clearance is distributed approximately evenly on the radially outer and radially inner sides of the roller. In a simpler case, the roller is radially centered and the radial distance from the outer surface of the roller to the inner surface of the housing is approximately equal to the radial distance from the outer circumference of the core to the radially inner and outer surfaces of the roller.

[0035] The radial clearance for a single roller in the second brake slit (generally) is preferably more than twice, and especially at least three times, the slit height in the first brake slit. This means that, under normal conditions, the roller has a larger clearance radially inward and radially outward than the slit height at the disc-shaped body in the first brake slit. It is also possible and preferred that the radial clearance for a single roller in the second brake slit is more than four times the slit height in the first brake slit. Preferably, the slit height at the brake slit at the disc-shaped profile is less than 0.15 mm, and more preferably less than 0.1 mm.

[0036] 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.

[0037] In the specific design, the radial clearance for one roller in the second brake slit is approximately 0.2 mm, while the slit height in the first brake slit is approximately 0.05 mm. Here, a deviation of + / - 50% may exist respectively. Therefore, because rollers are provided on opposite sides of the core, the radial clearance in the roller region at the tactile operating button is generally twice the radial clearance, which is 0.4 mm in this example. In the region of the first brake slit with a slit height of 0.05 mm, a radial clearance of 2 × 0.05 mm, or 0.1 mm, appears overall.

[0038] Because the gap is very small, in many cases, a separate support can be omitted, at least at the disc-shaped end of the tactile operating device. The disc-shaped profile then works together with the housing to guide or support the housing relative to the core. This allows for a simpler and less expensive structure.

[0039] In all designs, the inner contour, or preferably the shell, can be non-circular (e.g., elliptical). The core can also be mounted eccentrically relative to the shell. This results in a varying relative clearance (local) during rotation.

[0040] In a particularly preferred design, the first and second brake gaps are formed on different axial sides of the electric coil. More preferably, at least one brake gap is axially adjacent to the electric coil, either indirectly or directly.

[0041] The axial width of the roller is preferably between half and twice the axial width of the disc profile. This allows for particularly efficient transmission of the magnetic field in the brake slot of the disc profile, thereby also allowing for a high concentration of the magnetic field in the second brake slot within the roller region. This enhances the braking effect in both the first and second brake slots while maintaining a short axial structural length.

[0042] The ratio of the axial width of the roller to the axial width of the coil is preferably between 1:5 and 3:1, and in a preferred design it is between 2:3 and 3:2.

[0043] The ratio of the axial width of the disc profile to the axial width of the coil is preferably between 1:5 and 3:2, and in a preferred design between 2:3 and 3:2. Here, the axial width of the disc profile refers to the width of the disc profile at the brake gap. If the disc profile should, for example, narrow radially outward and the axial width of the disc profile decreases radially outward, it refers to the axial width of the disc profile near the radially outer end.

[0044] 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, and particularly preferably substantially radially, passes through the third braking gap. Furthermore, a substantial portion, and especially 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 conducted radially outward at its respective end and exits at one axial end through a disc-shaped profile and the first or second braking gap, respectively, and at the other axial end enters the housing from the core through the third braking gap, or vice versa. This design allows for a particularly simple, low-cost, and efficient structure.

[0045] The roller is preferably made of at least part, and especially almost entirely or completely, a magnetically conductive material.

[0046] Magnetic objects or rollers can also be used. Non-conductive objects can be used as placeholders or guides and can have any shape. Therefore, non-magnetic objects can be placed between (magnetic) rollers. Multiple non-conductive objects (such as guides) can be connected to each other, for example, in a cage-like manner. This simplifies installation.

[0047] Particularly preferred is that the disc-shaped profile rotatably guides the housing and serves as a support.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] A torque sensor can measure this torque.

[0059] Data acquired by sensor devices can be further processed by electronic devices and also forwarded to external devices. If, for example, tactile operating devices are installed in the vehicle as knobs / pressors (in the steering wheel, center console, onboard computer, etc.) to control the radio and / or navigation system, change chassis settings, etc., then data regarding angle changes can be transmitted within the vehicle to the onboard computer / vehicle electronics / external electronic devices. Information about road conditions and / or user characteristics can be recorded, evaluated, and optimized. Artificial intelligence can then deduce user expectations and optimize / simplify instrument control.

[0060] 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 the axial sides and radially outwards. The shielding mechanism preferably includes at least one isolation unit disposed 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 disposed between the shielding body and the housing. The isolation unit and / or 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 spaced apart from each other.

[0061] Shielding mechanisms can significantly improve measurement quality. In particular, they enable the acquisition of fine angular resolution and small axial distances.

[0062] In all designs, it is preferable to form a knob or rotating wheel on the housing. The knob can be formed by a coating.

[0063] Preferably, it includes a light-emitting element that has at least one knob that is at least partially transparent for illumination.

[0064] Preferably, a magnetic field strength greater than 300 kA / m can be obtained between some magnetically polarizable particles. This is certainly when the electric coil generates the maximum magnetic field or the magnetic field within a predetermined rated range. The (generable) magnetic field strength within the braking gap is preferably greater than 500 kA / m.

[0065] Preferred in all designs is a drive mechanism that includes at least one for actively rotating one of the braking components. This allows not only braking torque to be generated but also active rotation, thereby providing extended tactile feedback.

[0066] The instrument component of the present invention includes a tactile operating device as described above. It may also include two or more tactile operating devices. Such an instrument component may include a user interface, an operation panel, a display, a touch-sensitive display with or without tactile feedback, and / or at least one sensor or other possible input and output methods.

[0067] The user interface can be charged, in particular, via inductive coupling. Because the knob and, consequently, the external braking component of the user interface are rotatable, the cable for electrical connection cannot be immediately routed to the external end. Contact via a coil spring or sliding contact is possible, but this increases the base torque and is therefore not particularly preferred.

[0068] An inductively coupled coil is installed in the LED or light-emitting area, which can be used for both energy transfer and data transmission. Therefore, the required electrical energy is inductively transmitted to the user interface, and data is transmitted for display. Data links can also be implemented wirelessly.

[0069] The control of the magnetic coil is preferably performed mostly or primarily during the operating time at a voltage, especially 12 V. 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 is sometimes only achievable with a higher voltage. Maximum braking torque is typically obtained through the maximum magnetic field within the braking gap. Since 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 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).

[0070] Preferably, in the preferred design and improvement, 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. This allows the system to react more quickly and adjust to the desired braking torque more rapidly. This results in a more rectangular shape. A (approximately) stepped variation curve can be adjusted.

[0071] Especially in modern electric vehicles, multiple voltages and high currents are available within the vehicle, 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 such current intensities, allowing the aforementioned properties to be utilized advantageously.

[0072] The applicant reserves the right to claim protection for a method according to this application. This method is used for tactile control of a device having at least one magnetorheological braking mechanism. The magnetorheological braking mechanism includes two (or more) braking components. These two braking components are movable relative to each other. The first braking component includes a core made of a magnetically conductive material. At least one braking gap (slit) at least partially filled with a magnetorheological medium is formed between the first and second braking components. At least one electric coil applies a controllable magnetic field to the braking gap. To obtain a faster, and particularly stepped, change in braking intensity, at least one power parameter of at least one electric coil is changed more strongly in the initial stage of the change than is required for a longer duration to obtain the desired braking intensity.

[0073] This method of the present application is also very advantageous. It allows for better control of the braking action. In particular, improved voltage response can be obtained. A stepped braking action variation process can be achieved. Thus, the braking intensity can vary more "rectangularly" than in conventional control. Preferably, at least one power parameter of the coil changes by at least 10%, 20%, 30%, 50%, or 100% more in the first time period compared to the second time period relative to the previous time period.

[0074] In particular, the length of the second time period is more than 3 or 5 times that of the first time period. Preferably, the length of the first time period is between 3 ms and 30 ms, especially between 5 ms and 20 ms. In a specific design, the first time period can be approximately 10 ms + / - 5 ms.

[0075] In a preferred improvement, the current and / or voltage of the electric coil are changed to alter the braking intensity. Particularly preferred is that the voltage is changed as a power parameter.

[0076] Preferably, the power (power parameters) of at least two coils is changed.

[0077] The brake gap may include at least two or three brake gap sections. More than two brake gaps may also be provided. In particular, at least two brake gap sections may be subjected to the magnetic fields of different coils.

[0078] It is possible and preferred that, in order to form a tactile stop or a sensory grid, the power parameter (at least one power parameter, especially voltage) of at least one coil is set to be higher for a first time period than for a second time period when it increases (relative to the previous moment), the second time period being adjacent to the first time period and longer than the first time period.

[0079] In a preferred embodiment, the method is performed using an apparatus as disclosed in the scope of this application. Therefore, such an apparatus may have some or all of the features described in all claims. The method can be performed using the features disclosed in the scope of this application. Corresponding uses are also possible.

[0080] The invention claims application in tactile operating devices with braking mechanisms to generate high braking torque over a wide speed range, wherein the braking mechanism comprises at least two distinct radially formed braking slits. A disc-shaped profile is formed, for example, between a housing and a core, in the first braking slit to generate high braking torque at higher speeds. In the second braking slit, for example, a plurality of rollers are arranged on the circumferential surface of the core to generate high braking torque at lower speeds. For use, designs or modifications of tactile operating devices or instrument components as described above or within the scope of the following embodiments are particularly employed.

[0081] In all designs, the operating or actuating device can also be speed-increasing or speed-reducing via a transmission mechanism, belt (toothed belt / flat belt), linkage, or other means, resulting in different operating angles and rotation angles for the connected braking mechanism.

[0082] Tactile operating devices or tactile operating or actuating devices can also be designed as joysticks or levers. Joysticks can also be speed-increasing or speed-reducing mounted via transmission mechanisms, belts (toothed belts / flat belts), linkages, or other means, so that the operating angle and rotation angle of the preceding braking mechanism are different.

[0083] In all improvements and designs of tactile operating devices, operating or actuating devices, or instruments equipped with them, at least one drive mechanism may be included for actively rotating one of the braking components. Preferably, the operating button, operating wheel, or rotating unit is actively rotating. This allows for more tactile feedback to the user. Attached Figure Description

[0084] Other advantages and features of the present invention arise from the embodiments described below with reference to the accompanying drawings, wherein:

[0085] Figures 1a to 1b A three-dimensional schematic diagram of a tactile operating device with a magnetorheological braking mechanism is shown;

[0086] Figure 2 A side view of a tactile operating device with a magnetorheological braking mechanism is shown;

[0087] Figures 3a to 3c Different cross sections of the tactile operating device are shown;

[0088] Figures 4a to 4b A highly schematic illustration of the sensor device and measurement results is shown;

[0089] Figure 5 A highly schematic illustration shows a tactile operating device with a speed plate in different positions;

[0090] Figures 6 to 8 Another tactile manipulation device is shown in cross-sectional view;

[0091] Figure 9 A highly schematic circuit for controlling an electric coil is shown; and

[0092] Figure 10 Torque curves for the electric motor and magnetorheological braking mechanism relative to electrical input power are shown;

[0093] Figure 11 The braking torque curves of the magnetorheological braking mechanism with respect to time for two different current intensity curves are shown.

[0094] Figure 12 A schematic diagram of a tactile operation or actuation device with a drive mechanism according to the present invention is shown. Detailed Implementation

[0095] Figure 1a and Figure 1b Two different tactile manipulation devices 100 according to the invention are shown, each comprising a magnetorheological braking mechanism 1 and which can be used at different instrument components 200.

[0096] Figure 1a A tactile operating button 101 is shown as a tactile operating device 100. The operating button 101 is fixed by a bracket 50 and can be installed, for example, in a motor vehicle. The operating button 101 is operated by a housing 13 or a rotating element mounted thereon. The user interface 43 can also be used to transmit information.

[0097] exist Figure 1b In the diagram, instrument component 200 is shown as a thumb wheel 102 with a tactile operating device 100. The thumb wheel 102 is preferably used, for example, in a motor vehicle steering wheel. However, the thumb wheel is not limited to these applications. The thumb wheel 102 can generally also be used with any other finger or multiple fingers simultaneously, depending on the mounting configuration.

[0098] The tactile operating device 100 can be used, for example, to operate machines, medical instruments, computer game consoles, music terminals, input devices, or in and for use in motor vehicles. In motor vehicles, the tactile operating device 100 can be used, for example, to operate air conditioners, radios, entertainment systems, navigation systems, distance control systems, driver assistance systems, waste utilization adjustment systems, for adjusting seats, and for using infotainment systems. It can also be applied to other instruments or other devices.

[0099] Figure 2A side view of a tactile operating device 100, which can be used as an operating button 101, is shown. The tactile operating device 100 includes a support 4, which can be fixed to a bracket 50, for example, by a nut 51. The tactile operating device 100 includes a magnetorheological braking mechanism 1 with two braking components 2, 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.

[0100] The tactile operating device 100 has a compact structure and includes, within the shielding mechanism 75 which comprises a shielding body 76 in two parts as a cover, a sensor device 70, not visible here, for detecting the rotational and axial positions of the housing 13. The housing 13 is connected to the left cover 14 and the right cover 15 via pins 16 to seal the internal closed cavity 10.

[0101] exist Figures 3a to 3c For example, it is drawn in the middle. Figure 2 A possible cross-section of the tactile operating device 100 according to the invention. Here, the tactile operating device 100 includes a magnetorheological braking mechanism 1. A braking member 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 housing 13 that serves as an outer braking member or a second braking member 3.

[0102] The magnetic core 21 is surrounded by an electric coil 26 wound around the core 21. The electric coil extends across 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.

[0103] The core 21 can be made of sintered material (metal). The core can therefore be easily manufactured in the desired shape.

[0104] 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.

[0105] Some 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 shown.

[0106] The disc-shaped profile 41 is axially adjacent to the coil 26, which is housed in the coil holder 26b and is completely sealed radially outward by the filler 28.

[0107] 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 for the formation of holes or recesses for the cable 45 for electrical connection of the coil 26 to pass through. The coil 26 can thus be connected simply, inexpensively, and quickly.

[0108] Here, a disc-shaped profile 41 is formed at the proximal end, i.e., the end of core 21 facing support 4. A brake slit 5b is formed at the distal end, i.e., the other end of core 21. This brake slit 5b extends across an axial width 11e. Rollers 11 are distributed there on the circumferential surface of core 21. The rollers 11 locally enhance the magnetic field. The rollers 11 can form a magnetic field concentrator 80 to locally enhance the magnetic field as they pass through the brake slit 5b.

[0109] High braking torque can be obtained through the brake slit 5b, especially at low speeds of the housing 13. A stronger magnetic field can be transmitted from the core 21 into the housing 13 through the brake slit 5a in the region of the disc-shaped profile 41, because the slit height 41b is significantly smaller than the radial clearance 11c within its brake slit 5b region. This results in high torque, achievable even at higher speeds. Consequently, high torque can be provided across the entire speed range.

[0110] The axial width 11e of the brake slit 5b and the width 41e of the brake slit 5a are approximately equal (+ / -25%) and together slightly shorter than the coil 26. Overall, a very compact structure is achieved.

[0111] 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 here depending on the situation or independent of the situation.

[0112] 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-shaped clicker 29 is designed to contact outwards.

[0113] Axial operation of knob 23 actuates the quick-acting piece or clicker, causing the housing 13 to move generally to the left. This axial movement can be detected by a sensor device 70 having a magnetic field sensor 72 within the support or first braking component 2, the magnetic field sensor being radially surrounded by a magnetic ring unit 71. The magnetic field sensor 72 is specifically designed as a Hall sensor 72 and detects the orientation of the radial magnetic field relative to the magnetic field sensor 72. Thus, the angular position of the housing 13 relative to the core 21 can be determined. The axial displacement of the housing 13 caused by the operation of the clicker 29 results in a relative axial displacement between the magnetic ring unit 71 and the magnetic field sensor 72, which determines the change in the intensity of the detected signal. This allows the operation of the clicker to be detected.

[0114] Figure 3b A slightly different illustration is shown of a tactile operating device 100 with a magnetorheological braking mechanism, wherein the difference here is... Figure 3a The overlay 49 or knob 23 is omitted.

[0115] Figure 3a and Figure 3b The main difference between them is that, Figure 3b A 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 with a rotating body 11 is provided at the near end of the housing 13.

[0116] 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.

[0117] Figure 3b Several magnetic field lines 8 are illustrated, 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) radially pass 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.

[0118] 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.

[0119] 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).

[0120] exist Figure 3b The O-ring 39 can be seen, which is relative to the housing 13 and the sealing cap 14.

[0121] Figure 3c A schematic cross-sectional view of brake slit portions 5a and 5b is shown. Brake slit portion 5b is shown on the left, where rollers 11 are schematically arranged around the core 21. The rollers are generally surrounded by a housing 13. Each roller has a diameter 11d. The radial slit height 11b is slightly larger than the diameter 11d. The radial clearance 11c is the difference between the slit height 11b and the diameter 11d. The radial clearance 11c is generally divided relatively evenly inward and outward in a radially concentric pattern.

[0122] 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 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 the carrier medium can be omitted (vacuum). In this case, only the particles 19, which are susceptible to magnetic field influence, are filled into the cavity 110.

[0123] 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.

[0124] 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.

[0125] 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).

[0126] In other designs, it is particularly preferred that the magnetically polarizable particles (especially when used as dry powders) (a significant portion) comprise non-spherical particles (non-spherical particles) in which 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] It has been shown that high magnetic field strength can be used to achieve particularly effective tilting and clamping of certain particles. Therefore, it is preferable to generate magnetic field strengths greater than 150 kA / m, 250 kA / m, or 500 kA / m within the braking gap. In particular, magnetic field strengths greater than 500 kA / m, 750 kA / m, or 1000 kA / m can be generated or will be generated within the braking gap.

[0134] 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.

[0135] The maximum volume fraction of carbonyl iron particles is also higher in powder form (approximately 74%) than in MRF with oil as a carrier medium, for example.

[0136] 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.

[0137] To illustrate the effect in more detail, refer to Figure 4 in the applicant’s national application WO 2018 / 215350 A1, whose interpretation of the effect is fully incorporated into the disclosure of this application in an appropriate manner.

[0138] exist Figure 3c The right side of the image shows a cross-section of the brake gap 5a in the region of the disc profile 41. The disc profile 41 provides a disc body 42, which is mounted on the core 21. Radially outward, there is a gap height 41b 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 brake gap 5b. The disc body 42 can be designed as a disc assembly 44 and includes a plurality of disc plates 46.

[0139] Only as an example Figure 3c The roller 11 is drawn with dashed lines in the right-hand portion to indicate the difference. It can be clearly seen that a smaller gap height is achieved in the case of the disc-shaped body 42. As a result, a large braking torque and a high magnetic field strength can be obtained and transmitted there, which in turn creates a correspondingly high magnetic field strength and braking effect in the other braking gap sections 5b.

[0140] Figure 4aThe 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.

[0141] 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.

[0142] 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 (pressing) 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 pressing of the operation button 101 can therefore be detected. This allows for confirmation of selection or setting.

[0143] 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.

[0144] Figure 5 A tactile operating device with a kinetic plate 29 in two different positions is shown in a highly schematic manner, with the unoperated position drawn on the left and the operated position shown on the right. In the left illustration, the kinetic plate protrudes outward and downward and is guided within the core by the guide mechanism 29a (but is not supported, so there is almost no friction).

[0145] exist Figure 5The volume 29b of the defined triangle can be seen in the right half of the image. Volume 29b is approximately represented by a three-dimensional cone. If the tactile operating button 100 is actuated and the quick-acting piece 29 moves from a rest position (out) into a linear position in the plane, the housing 13 moves axially downward relative to the first braking member 2. Thus, the axial section 22 of the shaft or the first braking member 2 is inserted into the interior of the housing 13. The volume change 29b of the quick-acting piece 29 is preferably sized to substantially correspond to the insertion volume of the first braking member 2. The insertion volume is calculated by multiplying the axial displacement 22 by the cross-sectional area of ​​the first braking member 2 on the shaft 12. By substantially approaching it with surface 29b, pressure formation within the cavity 110 can be minimized or prevented. Volume balance can also be provided by the membrane 31, as discussed previously.

[0146] Figure 6 A cross-sectional schematic diagram of another tactile operating device is shown, in which a first braking component 2 is fixed to a support 4, for example, with a headless screw. This design also includes two braking slits 5a and 5b, wherein a disc-shaped profile 41 is formed at braking slit 5a and a roller 11 or rotating body is accommodated on the circumferential surface of the core 21 at braking slit 5b. The roller is guided by a bracket 11f.

[0147] The disc-shaped profile 41 here has an outwardly convex outer profile 47 at its axial outer end, which is designed, for example, as a cone shape, but could also be designed as a journal shape. This leaves reservoirs 32 for magnetorheological particles in the corner regions, ensuring an adequate supply of magnetorheological particles to the braking gap. In particular, carbonyl iron particles are attracted from the environment and concentrated in the magnetic field transition region.

[0148] Screw 48 is used to fill or empty cavity 110.

[0149] Figure 7 and Figure 8 Two other embodiments of the tactile operating device are shown, in which in both cases the disc wheel 41 is designed with a brake slot 5a at the distal end.

[0150] exist Figure 7 The diagram schematically shows how the individual receiving ring for the roller 11 is secured to the core 21 in the brake gap 5b by a nut 40b.

[0151] Figure 8 One embodiment is shown in which the individual receiving ring for the roller 11 and the disc assembly 44 for the disc body 42 are respectively fixed to the core 21 by nuts 40b.

[0152] exist Figure 8 In the middle, cover 14 is installed at the front end (left end), and cover 15 is installed at the rear end.

[0153] The disc-shaped body 41 can be constructed as a single unit or it can be designed as a disc assembly 44 with multiple disc-shaped plates 46.

[0154] Overall, this provides a tactile operating device that can be manufactured at a very low cost, where at least one support member can be saved by means of the "support" of the disc-shaped profile 41, thereby reducing the structural height. Very low basic friction is achieved. Manufacturing becomes simple and low-cost due to the use of fewer parts. The fewer parts also improve error requirements by avoiding error chains. For example, a knob-shaped tactile operating button or a rotating component with a tactile operating mechanism can be used in very different fields.

[0155] If necessary, operation can be detected using a quick-acting element, quick-acting plate, or button. The knob can be illuminated, for example, using an LED. The knob body can then be partially or entirely designed in a milky-white color to achieve the corresponding control function.

[0156] Figure 9 A circuit for rapidly controlling coil 26 is schematically shown. Coil 26 (magnetic coil) can be controlled here, for example, by an H-circuit. It is shown here only by a switch. A voltage source 35a, having a lower voltage of, for example, 12V (or 3V or 6V; appropriate voltage depending on the application), provides the voltage for normal operation. For voltage peaks, a voltage source 35b, having a higher voltage of, for example, 18V or 24V (or, for example, 6V or 12V), is switched on for this purpose. The lower voltage source 35a is then temporarily disconnected. After the maximum current is reached, the higher voltage source 35b is again disconnected from the circuit and coil 26, and the lower voltage source 35a is switched on again. The switch here can be any electrical component, especially those capable of millisecond-level switching.

[0157] As a result, the current within coil 26 reaches the desired value more quickly. In one specific case, the desired current intensity is reached within 10 ms instead of 40 ms. The switching between voltages can be achieved through circuitry.

[0158] Figure 10The diagram illustrates two curves showing the resulting braking torque, with the generated braking torque (normalized and therefore dimensionless here, Y-axis) plotted above the electrical input power (normalized and therefore dimensionless here, X-axis). The curve for a BLDC motor (brushless DC motor) is shown on the left, and the curve for a magnetorheological braking mechanism is shown on the right. 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.

[0159] 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.

[0160] Figure 11 The braking torque curves (Y-axis) of the magnetorheological braking mechanism 1 for two different current intensity curves are shown above time (X-axis). Here, the dashed curve in the upper half of the figure shows the conventional curve, where the current intensity is directly increased to the desired current intensity. The voltage of the coil 261 can be used as a power parameter. At the beginning, the braking torque should be suddenly increased at the previous moment 270. For this purpose, the power parameter 271 is significantly increased at the previous moment 270. Specifically, it needs to be increased more strongly than it takes a long time to reach the braking torque to be adjusted later. The power parameter 271 is at least 10% or 20% higher than the second power parameter 272. Here it can even be higher. It can be clearly seen that the braking torque curve 265 reaches the desired value much more rapidly through the aforementioned excessive increase. This results in a better approximation of the box-shaped curve.

[0161] Here, for example, 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).

[0162] 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 only initiates for 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 made. This is extremely advantageous in many ways because a rapid stop and direct tactile feedback can be experienced. In reality, the difference between the two curves is quite noticeable.

[0163] Combinations of voltage and current are also possible. Voltages exceeding 24 volts or higher (such as exceeding 100 volts) are also possible.

[0164] Instead of a single coil, two or more coils can be used, designed differently (wire thickness, number of windings, materials, etc.) and powered by different sources to achieve a boosting effect.

[0165] Figure 12 A tactile operating device 100 for operating various instruments, mechanisms, and devices according to this application is shown, as described in this application and specification (preface, overview, description of embodiments, and claims). Rotation is achieved, for example, by a knob 23 (also in the form of an operating wheel). A steering unit or steering wheel may also be used for operation. The knob 23 or operating button 101 may be non-rotatably connected to the shaft 311.

[0166] The tactile operating device 100 can also be designed as a steer-by-wire device.

[0167] In this embodiment, and in all other embodiments, designs, and modifications, an actuator device 303 may be included to convert rotational motion into other motions. The actuator device 303 may also be electrically connected, in particular, to the operating button 101.

[0168] The rotation of the control button 101 is detected by means of the sensor device 70 and, for example, an angle sensor. Based on the rotation angle, the actuator device 303 then controls other components or actuators.

[0169] Here, a drive unit 307, designed as an electric motor, is connected to shaft 311. The operation button 101 can be actively rotated via the drive unit 307. Thus, the operation button 101 is (actively) rotated under specified conditions, such as, but not only during steering (simulation), to provide the operator with corresponding tactile feedback.

[0170] The movement of the operating button or rotatable operating element 101 can be purposefully braked by means of the magnetorheological braking mechanism 1. To control the braking mechanism 1 according to various parameters and, for example, angles, a drive device 307 is also provided, and a control device 302 can be provided here. The control device 302 is effectively connected to the sensor device 70 for this purpose.

[0171] The control device 302 also considers data from the auxiliary system 304, for example. This allows for the purposeful influence of the movement of the rotatable operating element 101 based on driving conditions. The control device 102 can also be effectively connected to other sensors not shown in detail here, so that behavior can be purposefully influenced based on other parameters.

[0172] The braking mechanism 1 is equipped with a safety device 306 that removes the magnetorheological medium 6, which is also not visible 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 can thus be selected, as described within the scope of this application and shown in other figures.

[0173] like Figure 12 The operating or actuating device 100 shown according to the invention can be used to rotate the operating or actuating unit, which is not shown in detail herein. The operating or actuating unit 101 is designed herein as a rotary knob, which is non-rotatably connected to the shaft 311.

[0174] The operating or actuating device 100 can also be designed as a steer-by-wire device for games (games; force feedback steering wheel), but is not limited thereto. For this purpose, the actuator device 303 is used to convert the steering motion performed by the operating or actuating unit 101 into (virtual) vehicle motion in (racing) games (such as Need for Speed; Project CARS; MotoGP; flight simulators…). For example, in the case of a motorcycle, the actuator device 303 steers the (virtual) entire or all of the wheels. The actuator device 303 is thus electrically connected only to the steering unit 101.

[0175] The rotational movement of the steering unit is detected by means of sensor device 70 and, for example, a steering angle sensor. Based on the rotation angle, actuator device 303 then rotates, for example, the wheels in a video game.

[0176] Here, a drive unit 307, designed as an electric motor, is coupled to the shaft (such as the steering shaft) 311. The drive unit 307 can actively rotate the steering unit 301. Thus, the steering unit 301 is driven to move, for example, when cornering or turning back, just like in a conventional mechanical steering system in a real vehicle.

[0177] The movement of the operating or actuating unit 101 can be purposefully braked by means of the magnetorheological braking mechanism 1. A drive device 307 is also provided to control the braking mechanism 1 according to various parameters and, for example, the steering angle; a (steering) control device 302 is thus provided. The (steering) control device 302 is effectively connected to the sensor device 70 for this purpose.

[0178] The steering control device 302 also considers data from the driving assistance system 304 or other game players or game conditions (simulator drivers; racing simulators, etc.). This allows it to purposefully influence the movement of the steering unit 301 based on driving conditions. The steering control device 102 can also be effectively connected to other sensors or information sources of the game console, not shown in detail here, so as to purposefully influence steering behavior based on other parameters.

[0179] The control button can also be used in industrial equipment, computer peripherals, automobiles, airplanes, etc., and can be supplemented by the aforementioned active components.

[0180] This invention provides a tactile manipulation device that is compact, robust, durable, and highly advantageous. The tactile manipulation device is particularly well-suited for use in the automotive industry, but can also be used in all possible instruments and machines.

[0181] A major advantage of this structure is that it eliminates the need for external cables, sensors, and electronics. This allows for a high IP rating in all design options, as everything is ideally concealed behind the mounting plate.

[0182] The coil is preferably completely separated from the space containing the magnetorheological medium, especially by filler.

[0183] Axial displacement can be achieved in the preferred design, where the liquid volume is moved internally. Sufficient space is preferably provided between the cap and the disc profile so that the medium (or liquid) (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 roller. That is, magnetic particles always flow towards the stronger field because they are attracted by the magnetic field gradient.

[0184] 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.

[0185] Two rows of magnetic field concentrators with different shapes are used as described above. The first brake slit 5a is equipped with a disc-shaped profile. The second brake slit 5b is equipped with rollers, and in particular, rollers. Rollers, and in particular rollers with circular inner rings, allow for high static torque. The disc-shaped profile allows for good magnetic field transmission and high torque at high speeds.

[0186] 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.

[0187] 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).

[0188] 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.

[0189] The design of the haptic operating device can also be enhanced by adding different lighting effects to the cover. A low-cost variation is to use a cover / cap with a transparent element that is illuminated from below by LEDs. For this purpose, the transparent sleeve can be mounted on the housing or machined into the cover, or the entire inner surface of the cover can be designed in this way (like an inverted basin). The transparent portion can be beveled at the edges to direct the light in the desired direction.

[0190] 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.

[0191] 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.

[0192] List of reference numerals

[0193] 1. Magnetorheological braking mechanism

[0194] 2,3 Braking components

[0195] 4 supports

[0196] 5 gaps

[0197] 5a Brake gap for 41

[0198] 5b is used for the brake gap of 11.

[0199] 6. Medium

[0200] 8. Magnetic field, field

[0201] 10. Sharp-angled areas

[0202] 11 Rollers

[0203] 11b 5b gap height

[0204] Radial gap in 11c 5b

[0205] The diameter of 11d 11

[0206] 11e 11 axial width

[0207] 11F bracket

[0208] 12-axis

[0209] 13. Shell

[0210] 14. Closed

[0211] 15. Closed, covered

[0212] 16 sales

[0213] 18 Light-emitting components

[0214] 19 Magnetic Particles

[0215] 20 Rotation axis, axial direction

[0216] 21 cores

[0217] 22 hubs

[0218] 23 Knobs

[0219] 26 coils

[0220] 26b Coil Holder

[0221] 26e Axial width

[0222] 28 Packing

[0223] 29 Speed-motion film

[0224] 29a Guiding Mechanism

[0225] 29b volume

[0226] 31 membrane

[0227] 32 storage units

[0228] 35A 12V voltage source

[0229] 35b 18V voltage source

[0230] 38 Seals

[0231] 39 O-rings

[0232] 40b nut

[0233] 41. Disc-shaped outline

[0234] 41b 5a gap height

[0235] axial width of 41e 5a

[0236] 42. Disc-shaped body

[0237] 42a Container

[0238] 43 User Interface

[0239] 44 disk group

[0240] 45 Cable

[0241] 46 Disc-shaped plate

[0242] 47 The resulting outer contour

[0243] 48 Filler screws

[0244] 49. Coating

[0245] 50 brackets

[0246] 51 Nut

[0247] 68 signal

[0248] 69 Amplitude

[0249] 70 Sensor Device

[0250] 71 Magnetic Ring Unit

[0251] 72 Magnetic Field Sensor

[0252] 75 Shielding mechanism

[0253] 76 Shielding

[0254] 77 dividing units

[0255] 78 Decoupling mechanism

[0256] 79 Sensor Circuit Board

[0257] 79a Needle-type contact

[0258] 80 Magnetic field concentrator

[0259] 100 Tactile Manipulation Device

[0260] 101 Operating Head

[0261] 102 Operating roller

[0262] 110 Closed cavity

[0263] 200 machine parts

[0264] 265 Braking Intensity

[0265] 266 First power parameter

[0266] 267 Second power parameter

[0267] 270 The moment before

[0268] 271 First period

[0269] 272 Second period

[0270] 302 Control Device

[0271] 303 Actuator Device

[0272] 304 Auxiliary System

[0273] 305 coercive mechanism

[0274] 306 Safety Devices

[0275] 307 drive unit

[0276] 311 axis

Claims

1. A tactile operating device (100) having a magnetorheological braking mechanism (1), said magnetorheological braking mechanism having a fixed support (4) and at least two braking components (2, 3), wherein, One of the two braking components (2, 3) is non-rotatably connected to the support (4), and the two braking components (2, 3) are rotatable 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 shell (13) extending around the first braking component (2). At least one surrounding braking gap, at least partially filled with a magnetorheological medium (6), is formed between the first braking component (2) and the second braking component (3). (13) At least one electric coil (26) is accommodated between the coil (21) and the core (21) and wound around the axis of rotation (20) and surrounding the core (21), characterized in that it includes at least two different radially formed brake slits (5a, 5b), wherein the first brake slit (5a) and the second brake slit (5b) are formed on different axial sides of the electric coil (26), and wherein a disc-shaped profile (41) is formed between the housing (13) and the core (21) at the first brake slit (5a), and wherein a plurality of rollers (11) are provided on the circumferential surface of the core (21) in the second brake slit (5b).

2. The tactile manipulation device (100) according to claim 1, wherein, The disc-shaped profile (41) is formed as a separate disc-shaped body (42) or integrally formed with the core (21).

3. The tactile manipulation device (100) according to claim 2, wherein, The disc-shaped body (42) is mounted on the core (21) and has a accommodating groove (42a) adapted to the core (21).

4. The tactile operating device (100) according to any one of claims 1 to 3, wherein, The disc-shaped profile (41) is connected to the core (21) and is pressed or threaded to the core (21).

5. The tactile manipulation device (100) according to claim 1, wherein, The disc-shaped profile (41) is designed as a disc assembly (44) with multiple disc plates (46).

6. The tactile manipulation device (100) according to claim 5, wherein, At least one disc-shaped plate (46) is formed as a punching component.

7. The tactile manipulation device (100) according to claim 5 or 6, wherein, The disk assembly (44) includes multiple disk-shaped plates (46) that are basically designed to be circular and non-circular.

8. The tactile manipulation device (100) according to claim 1, wherein, The disc-shaped profile (41) has an outwardly protruding outer profile (47) on at least one axial side.

9. The tactile manipulation device (100) according to claim 1, wherein, In the second brake gap (11a), the radial clearance (11c) between the housing (13) and the core (21) for a roller (11) is greater than the gap height (41b) in the first brake gap (5a).

10. The tactile manipulation device (100) according to claim 9, wherein, The radial clearance (11c) for a roller (11) in the second brake gap (11a) is more than twice the gap height (41b) in the first brake gap (5a).

11. The tactile manipulation device (100) according to claim 1, wherein, The axial width (11e) of the roller (11) is between half and twice the axial width (41e) of the disc profile (41).

12. The tactile manipulation device (100) according to claim 1, wherein, The ratio of the axial width (11e) of the roller (11) to the axial width (26e) of the coil (26) is between 1:5 and 3:2, and wherein the ratio of the axial width (41e) of the disc profile (41) to the axial width (26e) of the coil (26) is between 1:5 and 3:

2.

13. The tactile manipulation device (100) according to claim 1, wherein, The magnetic field (8) of the magnetic circuit passes at least partially through the core (21) and the housing (13) in the axial direction, and passes substantially in the radial direction through the first brake slot (5a) and the second brake slot (5b).

14. The tactile manipulation device (100) according to claim 1, wherein, The disc-shaped profile (41) rotatably guides the housing (13) and serves as a support.

15. The tactile manipulation device (100) according to claim 1, wherein, The gap height (41b) at the brake gap portion (5a) at the disc-shaped profile is less than 0.15 mm or less than 0.1 mm.

16. The tactile manipulation device (100) according to claim 1, wherein, A closed cavity (110) is formed between the braking components (2, 3), and at least a considerable portion of the closed cavity (110) is filled with a magnetorheological medium (6).

17. The tactile manipulation device (100) according to claim 1, wherein, The second braking component (3) is axially movable and accommodated on the first braking component (2).

18. The tactile manipulation device (100) according to claim 16, wherein, A clicker (29) is provided at the distal end (115) of the closed cavity (110).

19. The tactile operating device (100) according to claim 18, wherein, An elastic membrane (31) separates the closed cavity (110) from the click element (29).

20. The tactile manipulation device (100) according to claim 18 or 19, wherein, The clicker is designed as a slewing piece, wherein a change in the defined volume of the slewing piece is adapted to the cross-sectional area of ​​the shaft multiplied by the shaft misalignment of the slewing piece during operation.

21. The tactile manipulation 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).

22. The tactile manipulation device (100) according to claim 1, wherein, Includes a sensor device (70) for detecting the relative axial position of the housing (13) relative to the braking component (2).

23. The tactile manipulation device (100) according to claim 21 or 22, comprising a shielding mechanism (75) for at least partially shielding the sensor device (70) from the magnetic field of the coil (26).

24. The tactile manipulation device (100) according to claim 23, wherein, A light-emitting element (18) includes a knob (23) that is at least partially transparent and housed on the housing (13) for illuminating a light source.

25. The tactile manipulation device (100) according to claim 1, wherein, The magnetic field strength between particles that can be individually magnetically polarized is greater than 300 kA / m.

26. The tactile manipulation device (100) according to claim 1, wherein, The magnetic field strength within the braking gap is greater than 500 kA / m.

27. The tactile operating device (100) according to claim 1, comprising at least one drive device for actively rotating one of the two braking components (2, 3).

28. An operating button (101) having a tactile operating device (100) according to any one of claims 1 to 27.

29. An instrument component (200) having a tactile operating device (100) according to any one of claims 1 to 27.

30. The instrument component (200) according to claim 29, comprising at least one user interface (43), an operation panel, a display, a touch-sensitive display with or without haptic feedback, and / or at least one sensor.

31. A tactile operating device with a braking mechanism is used for applications that generate high braking torque over a wide speed range, wherein, At least one electric coil (26) wound around and surrounding the core (21) about a rotation axis (20) is accommodated between the housing (13) and the core (21), wherein the braking mechanism includes at least two different radially formed braking slits (5a, 5b), wherein the first braking slit (5a) and the second braking slit (5b) are formed on different axial sides of the electric coil (26), wherein a disc-shaped profile (41) is formed between the housing (13) and the core (21) at the first braking slit (5a) to generate a high braking torque at a higher speed, and wherein a plurality of rollers (11) are arranged on the circumferential surface of the core (21) in the second braking slit (5b) to generate a high braking torque at a lower speed.

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