Device with a magnetorheological braking system

Abstract

The device (100) comprises a magnetorheological braking device (1) with two braking components (2, 3) movable relative to each other and each having a component body, and with a magnetic field generation device (26) for generating a magnetic field, wherein a gap (5) is formed between the braking components (2, 3) and includes an effective gap region (10) equipped with a magnetorheological medium (6). The magnetic field of the magnetic field generation device (26) passes through the component bodies (20, 30) of the braking components (2, 3) and through the effective gap region (10) in order to influence the magnetorheological medium (6) and thus the relative mobility of the two braking components (2, 3) relative to each other. A component body (20, 30) of a braking component (2, 3) comprises a contact section (21, 31) adjacent to the effective gap region (10) with a property different from that of the component body (20, 30).

Description

The invention relates to a device having at least one magnetorheological brake device with at least two brake components movable relative to one another. The brake components each include a component body. At least one magnetic field generating device serves for generating a magnetic field. At least one gap section is formed between the brake components. The gap section comprises at least one effective gap region equipped with a magnetorheological medium. The magnetic field of the magnetic field generating device runs through the component bodies of the brake components and passes through the effective gap region in order to influence the magnetorheological medium and thus a relative movability of the two brake components relative to one another.Such devices can be designed, for example, as an operating device and serve for setting operating states. Then, by means of the magnetorheological brake device, for example, different moments or forces, stops and rasters can be set for the movements. Thus, during operation, a haptic (perceptible) feedback can be transmitted, which supports the user and allows very specific settings and reduces overall the operating complexity. Such control devices are used more and more frequently in a wide variety of devices and, for example, in motor vehicles or medical technology or also in smart devices, in order, for example, to select menu items or to perform precise controls. Moreover, such devices are becoming more and more widely used in the operation of computers and game consoles. The device can be constructed very compactly and at the same time reliably and should have the smallest possible basic moment, but must also generate a high maximum moment in particular.It is also possible to use them in larger actuators for different applications. Not only but also, for example, in steering specification devices for specifying a steering movement according to the steer-by-wire concept.A decisive feature of such devices is a high maximum torque or a high braking force that can be generated with a relatively low basic torque or basic force. It is advantageous if the installation space and the weight remain small.It is therefore the object of the present invention to provide a device with an improved magnetorheological brake device which meets the requirements discussed above in a particularly advantageous manner.This object is achieved by a device having the features of claim 1. Further advantages and features of the present invention are evident from the general description and from the description of the exemplary embodiments.The device according to the invention comprises at least one magnetorheological brake device. The magnetorheological brake device comprises at least two brake components which are movable relative to one another and each have a component body and at least one magnetic field generating device for generating a (in particular controllable) magnetic field. At least one gap portion (at least one gap) is formed between the brake components. The gap section comprises at least one effective gap region equipped with a magnetorheological medium. The gap section or the entire gap can also be equipped overall with at least one magnetorheological medium.The effective gap region is at least partially or almost completely or completely filled with a magnetorheological medium. The magnetic field of the magnetic field generating device runs through the component bodies of the brake components and passes through the effective gap region between the brake components. The magnetorheological medium in the effective gap region is influenced by the magnetic field and thus a relative movability of the two brake components relative to each other is influenced. At least one brake component comprises a contact section adjoining the effective gap region and having a different nature from the component body. This means that on the surface of the brake component adjoining the effective gap region, a contact portion is provided, the nature of which differs from the nature in the component body (per se).The device according to the invention offers many advantages. A considerable advantage is that the contact section makes it possible to provide other properties on the surface of the effective gap region which differ from the properties of the component body (directly adjoining the contact section) per se. As a result, on the one hand, the maximum braking torque (braking force) can be increased and, on the other hand, the basic torque (basic friction) can be reduced.The component body itself is usually made of a material having a high relative magnetic permeability. In the context of this application, the relative magnetic permeability is also referred to as magnetic conductivity. For example, the component body can consist (to a substantial extent or completely) of soft magnetic, ferrimagnetic and / or ferromagnetic materials.Preferably, the contact portion has a (substantially) higher hardness than the material of the component body. A ratio of hardness or degrees of hardness may be greater than 2 or 5 or 10. It has been found that higher hardness at the surface of the component body is expected to result in improved properties. Thus, with a higher hardness of the component section, a lower basic friction can be achieved, while the maximum achievable braking force or the maximum achievable braking torque does not change or even increase. This was not expected and is surprising. In principle, a higher hardness leads to a reduced sliding friction. Therefore, the ratio of maximum to minimum effect (force or moment) could be expected to reduce, but this does not occur. This could be because the clamping effect of the magnetorheological particles in the magnetorheological medium exposed to a magnetic field and therefore wedged does not decrease and is passed on to the harder contact surfaces in a constant or stronger manner since they are not so flexible.The contact surface of the contact portion and / or a substantial portion of the surface (or the entire surface) of at least one brake component may be (physically and / or chemically and / or mechanically) hardened. In particular, the hardness of the contact portion (at the contact surface) can be increased by sandblasting and preferably by shot peening. The surface can also be hardened by laser hardening, electron beam hardening or induction hardening.Preferably, a standard method is used as the hardness test method for determining or specifying the hardness. For example, the hardness can be given according to Vickers HV or according to Rockwell HRC. The hardness can be determined, for example, by the penetration depth or test force or impression surface at a specific load.Preferably, the hardness of the contact portion is in a range of 330 HV to 1000 HV according to Vickers. The hardness of the component body is preferably equal to or lower than 350 HV according to Vickers. Preferably, the hardness of the contact portion is in a range of 34 HRC to 68 HRC according to Rockwell. The hardness of the component body is preferably less than or equal to 34 HRC according to Rockwell.In the prior art, without the invention, certain noise may sometimes arise in some operating ranges due to the continuous chaining of the particles under the influence of a magnetic field and tearing loose during a relative movement of the brake components with respect to one another. A further advantage is that a type of slideback under the influence of a magnetic field, also called an stick-slip effect, can be better avoided with the invention.In preferred configurations, the contact portion (on the contact surface) has a better sliding quality (in particular a smaller coefficient of sliding friction) than it would have a identically structured surface made of the material of the component body. This results in a lower friction (sliding friction and / or static friction) with respect to the magnetorheological particles in the magnetorheological medium, but the clamping effect is not reduced.The coefficient of static friction of the contact surface is preferably in a range from 0.04 to 0.2.Preferably, a roughness of the contact surface of the contact portion is small. Specifically, the average roughness index or the average roughness Ra (index Ra, the arithmetic average of the roughness) is small.Preferably, the average roughness Ra of the contact surface (in particular in the effective gap region) of the brake device is in a range of 0.005 μm and 0.15 μm. Smoother surfaces reduce the friction and thus also undesired effects due to a judder release or stick-slip effects.It has been found to be advantageous to reduce friction and / or to increase smoothness and in particular to reduce the average roughness even on surfaces outside the effective gap region. This reduces the (random) friction of particles even at locations outside the (actual) effective gap in the gap section or the gap. The basic friction can be reduced and thus improved by an improved smoothness even outside the effective gap region.The magnetorheological medium can be a fluid in which magnetorheological particles are present. The fluid can be a gas (such as air) or a liquid such as an oil. A gel is also possible.Preferably, the contact portion has a different microstructure than the component body. For example, the contact section can itself consist of the same (or else of a different) material and can be compacted, for example (on the surface). Microstructure is understood here not as the outer shape, but rather as the inner structure of the material. In particular, the microstructure is understood to mean the grain structure of the material.Preferably, the contact portion has a lower magnetic conductivity than the material of the component body. Surprisingly, this leads not to a reduced but to improved braking properties. The ratio of maximum effect to minimum effect (force or moment) is improved.The contact section is preferably designed as a surface layer and in particular as a surface coating on the component body. The surface coating can be applied in particular galvanically or mechanically. It is possible and preferred to apply at least one layer by chemical vapor deposition ("chemical vapor deposition") or physical vapor deposition ("physical vapor deposition"). Such a coating is often carried out under vacuum. The coating can also be effected by wet application.Preferably, the contact portion comprises at least one layer of amorphous carbon. The use of plasma polymer layers is also preferred.Preferably, the contact portion includes at least one layer of a group of layers including layers including titanium nitride, titanium aluminum nitrite, titanium carbon nitrite, titanium aluminum carbonitride, titanium carbide, and titanium carbonite layers. A layer or coating with titanium as a constituent is very advantageous and more favorably applied than DLC layers. This is advantageous for medium-volume production or large-volume production. An increase in the hardness and / or strength can also be effected by applying (high) pressure.The contact portion may also comprise at least one nanocoating. At least one layer made of nanocomposite or a layer which chemically bonds the three elements aluminum, titanium and nitrogen is also possible. It is also possible to use composite layers, for example of SISTRAL and / or zirconium carbonitride ZrCN. Plasma layers and / or PVD hard material coatings can also be used.In all configurations and developments, the contact section can consist of one layer or else of a plurality of layers. The contact section can preferably have a plurality of layers (multilayer layers) (different layers and / or layers applied one after the other).In a particularly preferred embodiment, at least one component body of at least one brake component comprises at least one layer adjoining the effective gap region as part of a contact section (or directly as a contact section). The layer has a different nature from the component body. This means that at the surface of the brake component adjoining the effective gap region, at least one layer (as a contact section) is provided, the nature of which differs from the nature in the component body (per se).Side parts or covers, which delimit or seal the brake components (the brake body), can also comprise a contact section. Different contact portions can be applied to different components.The type of contact portion (each) selected is related to the properties of the magnetorheological particles (size distribution, shape, composition, particle coating, etc.) and can vary accordingly. Various curing and / or coating methods can also be applied to the individual components.In all embodiments, the contact portion can be distinguished from the component body by measuring the physical and / or chemical properties. The transition from the contact portion into the (remaining) component body may be smooth when about some of the surface has diffused into the brake component.Preferably, the contact section is formed as a thin film. A layer thickness can be a few micrometers. A contact section with (at least) one layer of amorphous carbon is advantageous. Amorphous carbon may also be referred to as diamond-like carbon (DLC) or diamond-like carbon. It is possible-in particular, but not only-to use amorphous carbon layers according to VDI 2840 and ISO 20523. Another possible coating is modified amorphous carbon (XLC).In preferred refinements, the contact section is applied as a separate part to the component body. The contact section can be pressed on or glued on, for example.Preferably, in all configurations, a thickness of the contact portion perpendicular to a contact surface with the effective gap portion is less than 2 mm or less than 0.5 mm and in particular less than 0.1 mm or 0.05 mm. The thickness may also be less than 20 μm or 10 μm.Specifically, a ratio of a thickness of the component body perpendicular to a contact surface to a thickness of the contact portion (measured in the same direction) is greater than 10 or 100. Preferably, a ratio of a thickness of the component body (perpendicular to a contact surface) to a thickness of the contact portion (in the same direction) is greater than 10 or 100.In preferred embodiments, both brake components each have at least one contact section or also a plurality of contact sections.Preferably, the brake components are accommodated in a longitudinally displaceable manner (and in particular in a linearly displaceable manner) relative to one another and / or the brake components are accommodated in a pivotable manner relative to one another (and in particular rotatable about an axis of rotation).Particularly preferably, one of the brake components is designed as an inner brake component and the other brake component is designed as an outer brake component.Preferably, the effective gap region extends (in the circumferential direction) around a brake component (partially or completely).It is preferred that the effective gap region extends (in the axial direction) along a brake component.In particular, the gap section and also the effective gap region are formed (in the circumferential direction) circumferentially around one of the brake components. An (axial) length of the effective gap region can be greater than a circumference of the effective gap region. The gap section can have at least one or also at least two or more effective gap regions or separate effective gap sections and / or sections separated from one another.In particular, the magnetic field of the magnetic field generating device runs through the brake components and the effective gap region of the gap and thus also through the magnetorheological medium accommodated in the effective gap region.The magnetic field generating device preferably comprises at least one electric coil device.In an advantageous embodiment, at least one of the brake components comprises at least one coil receptacle. In particular, at least one electric coil device of the magnetic field generating device is accommodated in the coil receptacle.The coil receptacle is formed in particular as an (integral) component of one of the brake components. The coil receptacle comprises in particular at least one receiving space and in particular at least one wall arrangement at least partially surrounding the receiving space. In particular, the coil receptacle (preferably at least the wall arrangement) is at least partially magnetically conductive.In advantageous configurations, at least a part of the gap in the effective gap region has a periodically variable effective gap height. For this purpose, a contour of a brake component can protrude into the effective gap region. The contour can be formed, for example, as a star contour or the like.It is possible and preferred that a portion of the contact surface of a brake component is provided by a contact portion. It is possible that another portion of the contact surface of the same brake component is formed by a surface area of another contact portion or by the component body itself. Different contact portions may be provided. It is also possible that only a part of the contact surface is formed as a contact section.It is possible and advantageous for the magnetic field generating device to comprise at least one permanent magnet device or a permanent magnet for providing the magnetic field.In all embodiments, it is preferred that the effective gap region is separated or sealed off from the remaining gap or towards the outside by at least one sealing device.It is possible for a permanent magnet device to be provided by a component with magnetic remanent properties (so-called remanent device). Due to the remanent properties, the component maintains the respective magnetic state permanently or at least until it is re-demagnetized or magnetized. Such a component can be magnetized or demagnetized by the coil device if necessary. The component is, for example, one of the brake components or a section of such a component.In all configurations, it is preferred that the magnetorheological medium comprises magnetorheological particles and gas as filling medium. In particular, the magnetorheological particles are absorbed in air. In particular, the magnetorheological medium is designed as a powder. With such a magnetorheological medium, the invention presented here enables a particularly low basic torque. Alternatively, it is conceivable and possible for the magnetorheological medium to comprise magnetorheological particles and at least one carrier liquid, such as oil, water or alcohol.It is particularly preferred that the magnetorheological particles (each) consist predominantly of carbonyl iron powder or derivatives thereof. Other magnetorheologically responsive particles are also possible. The magnetorheological particles can have coatings for protection against abrasion and / or corrosion and / or additional components in order to make the magnetorheological particles more stable, abrasion resistant and / or lubricious during operation. The magnetorheological medium and / or the magnetorheological particles can comprise, for example, a graphite addition.In the context of the present invention, a magnetically non-conductive material is understood to mean, in particular, a material having a relative permeability of less than ten up to, for example, approximately 1. Magnetically conductive is understood here in particular to mean materials having a relative permeability of greater than ten and preferably ferromagnetic substances. The magnetic conductivity is the "relative magnetic permeability", which is also referred to simply as "magnetic permeability".The application or formation of a layer, a contact section, which is in particular harder than the magnetorheological particles and is also harder than the component bodies of the brake components, is proposed.Examples of suitable materials of the contact portions are ceramic layers. Particular preference is given to using a carbon layer such as an amorphous carbon (DLC="diamond-like carbon"). The layer thickness of DLC coatings can be in particular in a range from 0.5 μm to 2.5 μm, but can also be greater.Electroplating with other materials is also possible. Curing of the base components is also possible, carbon generally being incorporated into the surface of the base material for this purpose in order to achieve a curing. This is not a coating (by a different material), but a contact portion with different properties is also provided. A suitable curing method is case curing. Hardening reduces the magnetic conductivity in the contact portion. If this is thin enough, this has little or no effect.In all embodiments and developments, it is preferred that (at least) one magnetorheological auxiliary brake device is included. The additional brake device comprises two brake components that are movable relative to one another and each have a component body. Furthermore, at least one (additional) magnetic field generating device is assigned for generating an (additional) magnetic field. An (additional) gap section is formed between the brake components of the additional brake device and has at least one (additional) effective gap region equipped with a magnetorheological medium. The magnetic field of the (additional) magnetic field generating device runs through the component bodies of the brake components of the additional brake device and passes through the (additional) effective gap region in order to influence the magnetorheological medium and thus a relative movability of the two brake components of the additional brake device relative to one another.An additional braking device is advantageous and allows even finer control of the braking power. In particular, if the additional brake device differs from the brake device in at least one parameter or at least one dimension.In all cases, the brake device can also be referred to as a first brake device. The additional brake device can also be referred to as a second brake device.In particularly preferred embodiments, at least one (typical) characteristic of a contact surface of the magnetorheological brake device differs significantly and in particular significantly from a (typical) characteristic of a contact surface of the magnetorheological auxiliary brake device. Particularly preferably, a typical condition of at least a part of the contact surface of the brake device differs from a typical condition of a corresponding part of the contact surface of the additional brake device.The term "typical" means that a representative measure of the texture of the contact surface of the supplemental brake device is significantly (i.e., measurable and reproducible) different from the corresponding representative measure of the texture of the contact surface of the brake device.In particular, the entire surface may have a different hardness. It is also possible for (corresponding parts) of the surface (in the respective effective gap region) to have a considerably different measurable property. In particular, the hardness or softness, roughness, coefficient of static friction, coefficient of dynamic friction, smoothness, material or material composition, degree of polishing (starting at not polished at all) may differ significantly.Comparable surface locations are compared with one another. If both surfaces on the brake device and the additional brake device each have, for example, a star contour, then, for example, at least (some or all) "hillheads" and / or "hill flanks" are of different characteristics.The surface areas can also differ in material composition, smoothness, coefficient of static friction, coefficient of sliding friction or hardness. In particular, where the particles rub during braking.It is also possible that the perimeter averaged texture (average texture) differs significantly.Preferably, one of the brake components of the additional brake device is designed as an inner brake component and the other brake component of the additional brake device is designed as an outer brake component.In particular, at least one brake component of the additional brake device comprises a contact section of the additional brake device adjoining the (additional) effective gap region with a different characteristic from the component body of the additional brake device. For example, the contact portion of the additional brake device can be made of a different material than the contact portion of the brake device. It is also possible that the contact section of the additional brake device does not differ from the component body, so that the component body of the additional brake device directly provides or forms the contact surface in the effective gap area.In particularly preferred embodiments, the brake device has a lower braking capacity (force / torque) than the additional brake device (or vice versa).In particular, the contact section of the additional brake device is softer and / or rougher than the contact section of the brake device. This provides two fundamentally different braking devices, in which braking can be carried out more strongly by one, for example, and a braking effect can be more finely adjusted by the other. As a result, in the case of smaller braking forces or braking torques, jerk movements or possibly disturbing noises can be avoided.Preferably, the gap section of the brake device and the gap section of the additional brake device are at least partially formed at a common (continuous) gap. This facilitates sealing and permits a compact construction. It is also preferred that the gap section of the brake device and the gap section of the additional brake device are formed at least partially at different gaps and separate from one another. As a result, different magnetorheological media (for example different powders) can be used.In preferred embodiments, the two gap sections (gap section and the additional gap section) are separated from one another by at least one seal. It is also possible and preferred to use a common magnetorheological medium at a continuous gap.In preferred embodiments and refinements, the brake device and the additional brake device are designed as separate actuators.It is possible and preferred that the contact portion of the brake device and the contact portion of the additional brake device differ in terms of at least one property (nature) of their surface from a group of properties (natures) which comprises the roughness, the degree of polishing, the coefficient of static friction, the coefficient of dynamic friction, the material composition and the hardness.Preferably, the coefficient of static friction of the contact surface of the additional brake device is in a range from 0.15 to 0.6.In a preferred embodiment, the average roughness Ra of the contact surface of the auxiliary brake device is in a range of 0.1 μm and 60 μm.The hardness of the contact portion of the auxiliary brake device may be less than or equal to 350 HV according to Vickers and / or less than or equal to 34 HRC according to Rockwell.Preferably, the component bodies of the additional brake device form the contact surfaces (directly).A coated region as a contact portion, for example, can provide improved controllability and enable low-noise operation, with less adhesion and less sliding friction occurring. The braking torque may be lower.An uncoated region may allow for a higher braking torque.During operation, for example, the first brake device or the magnetic circuit with coating is used as long as the braking torque is sufficient. As soon as higher torques are required, the uncoated magnetic circuit or the additional brake device is "connected in".The inner brake component of the additional brake device can have, in particular, a cylindrical (disk-shaped) contour or also, for example, a star contour.In an advantageous development, at least one control device is provided, which is suitable and designed to control the magnetic field of the magnetic field generating device of the braking device and, if appropriate, of the additional braking device.The device can be designed as an operating device for setting operating states by means of rotational movements and / or linear movements. In particular, the movement resistance of the movement can be adjusted in a targeted manner. Such an operating device is, for example, a rotary knob or a joystick or the like.A device designed as a braking or clutch device can be used, for example, in a steering specification device for specifying a steering movement according to the steer-by-wire concept. In particular, one of the rotary components can then be coupled to a drive and one of the rotary components can be coupled to a drive output (e.g. to a steering wheel).Further advantages and features of the present invention result from the exemplary embodiments which are explained below with reference to the attached figures.Shown therein are: FIG. 1 shows a purely schematic representation of an apparatus according to the invention in a perspective view; FIGS. 2a-2d show possible constructions of the device according to FIG. 1 in sectional views; FIG. 3 shows the device according to FIG. 1 in a cross section; FIGS. 4a-4e are enlarged detailed views of possible embodiments of the device according to FIG. 3; FIG. 5 shows a further device in a side view; FIG. 6 is a cross-section through the brake device of the device according to FIG. 5 ; FIG. 7 is an enlarged view of a detail of the brake device according to FIG. 6 ; and FIG. 8 shows a schematic illustration of a further device according to the invention.FIG. 1 shows an apparatus 100 according to the invention having a magnetorheological brake device 1 with two brake components 2, 3 which can be rotated relative to one another. In the interior, a magnetic field generating device 26, which is not visible here, for braking the rotation capability of the brake components 2, 3 is shown.The device 100 can be an operating device or another actuator, for example. The brake component 3 (outer) here can be designed, for example, as a rotary knob or as a thumb roller. The braking device 1 then generates haptic feedback while the rotary knob or thumb roller is rotated to set operating states.However, the device 100 can also be designed, for example, as a steering specification device (for example as a component of a force feedback actuator) or as another actuator. The brake device 1 then serves, for example, as an actuator of a steer-by-wire steering unit of a vehicle or in a turning wheel or steering wheel of a game controller.The (inner) brake component 2 can be held in a rotationally fixed manner on a torque support, not shown here, and for example on an abutment structure (bracket, body, etc.). The outer brake component 3 is rotatably mounted on the inner brake component 2. For this purpose, a bearing unit 9 and, for example, a slide bearing can be provided (see FIG. 2 ).FIG. 2 ashows a possible internal construction of the device 100 of FIG. 1. a gap section 5 of a gap is formed between the brake components 2, 3. A magnetorheological medium 6 is arranged in the gap section 5. The magnetorheological medium 6 is provided in any case in the effective gap region 10 of the gap section 5. The effective gap region 10 can be separated within the gap section 5 by means of, for example, sealing devices 7 and form an effective gap section. However, the effective gap region 10 is in any case the region of the gap section 5 through which a considerable portion of the magnetic field 8 of the magnetic field generating device 26 passes. The magnetic field 8 of the magnetic field generating device 26, which here comprises an electric coil unit 26 a, is conducted inside the brake component 2 and enters the effective gap region 10 a(part of the effective gap region 10) of the gap section 5 at the contact surface 11 and enters the outer brake component 3 through the contact surface 12. There, the magnetic field 8 is guided axially through the brake component 3 and passes through the effective gap region 10 b(likewise part of the effective gap region 10) of the gap section 5 (the same gap section or another) and enters again into the inner brake component 2, where the magnetic field then closes. The effective gap region 10 (or here the two parts 10 aand 10 b) is (largely) filled with the magnetorheological medium 6, the particles of which are influenced by the acting magnetic field 8 and become linked or agglomerate and thereby exert a braking action on the brake component 2, 3.In other embodiments, two separate effective gap areas 10 aand 10 bmay also be used.The brake components 2, 3 here each have, on the contact surfaces 11, 12, a contact section 21, 31 whose nature differs from the nature of the component bodies 20, 30. It is also possible that a contact portion 21 or 31 is formed only on one of the contact surfaces 11, 12. It is also possible that a contact section 21 or 31 does not extend over the entire contact surface 11, 12 (in the effective gap region 10), but only over a part of the surface.The dimensioning of the gap section 5 and in particular of the effective gap region 10 is not drawn to scale here and in the other figures for reasons of visibility. For sealing the effective gap region 10 or the gap section 5, at least one sealing device 7 is provided.Here, a magnetic field 8 is generated via an electric coil device 26 afixed to the inner brake component 2 (here designed as a rotary component 2). The coil device 26a is supplied with current via cables 27 and controlled accordingly. The magnetic field influences the medium 6, so that the movability of the brake component 3 (here embodied as a rotary component 3) is acted upon by a targeted torque.The rotary component 2 is equipped with a coil holder. The coil device 26a for operating the brake device 1 is arranged in the receiving space. If necessary, a permanent magnet is also provided, the magnetic field of which is superimposed in a targeted manner with a magnetic field of the coil device 26 a.FIGS. 2 bto 2 d show possible embodiments of the internal structure of the device 100 from FIG. 1, wherein the device 100 has in each case two different brake devices 1 and 101 which differ (somewhat).Here, the brake device 1 is responsible for generating lower braking torques, while the additional brake device 101 is used for higher braking torques. The additional braking device 101 is (also) used for the locking or blocking and the braking device 1 for the targeted (gentle) and, for example, jerk-free and also lower-noise, slower and specifically controllable braking. For this purpose, both brake devices 1, 101 can have fundamentally the same geometric structure and also the same dimensions. Other dimensions are also possible. The difference in any case is the configuration and configuration of the contact surfaces to the effective gap regions, where the magnetic field from the brake components 2, 102 or 3, 103 respectively enters a gap section 5, 105.The brake device 1 has an inner component body 20 and an outer component body 30, which are rotatable relative to each other. At least one gap section 5 equipped with a magnetorheological medium is formed therebetween, through which the magnetic field 8 of the magnetic field generating device 26 passes. The gap portion 5 is adjoined by a contact portion 21 and a contact portion 31 of the inner and outer brake components 2, 3. The contact portions 21, 31 may be, for example, a coating harder than the base materials of the component bodies 20, 30. This reduces friction and further prevents judder. The transmittable braking torque can thereby be reduced, but is better controllable.In addition, the additional brake device 101 is provided, which has, for example, no (particularly hard or smooth) contact sections 121, 131. The additional brake device 101 enables a stronger maximum braking torque, for example for blocking. If the additional brake device 101 has contact sections 121, 131 applied to the component bodies 120 and 130, these are of a different nature than the contact sections 21, 31 of the brake device 1.In the exemplary embodiment according to FIG. 2 b, two complete brake devices 1, 101 are included, which have a common gap at which the gap sections 5, 105 are formed. A magnetic field generating device 26 selectively supplies the braking device 1 with a magnetic field 8 and the magnetic field generating device 26 supplies the braking devices 101 with a magnetic field 108. Each brake device 1, 101 has an inner brake component 2, 102 and an outer brake component 3, 103, each of which has a component body 20, 30, 120, 130. At least in sections, contact sections 21, 31 are formed on the component bodies 20, 30 on the brake device 1, so that the contact surfaces 11, 21 of the brake component 2, 3 have a characteristic that differs measurably from a characteristic of a surface of the material of the component bodies 20, 30. In particular, the surfaces of the component bodies 20, 30 are at least partially coated in the gap section 5 in order to increase the hardness and / or smoothness there.On the additional brake device 101 (second brake device 101), contact portions 121, 131 can be dispensed with. Or, the contact portions 121, 131 have different characteristics (characteristics) on the contact surface from the contact portions 21, 31 of the (first) brake device 1.Separating elements 140, 150 can be arranged between the brake device 1 and the additional brake device 101, which separate or magnetically isolate the two magnetic circuits from one another. The separating elements 140, 150 can consist of materials with poor magnetic conductivity (e.g. of metal, synthetic resin etc.) and provide for a better separation of the magnetic circuits.The two brake devices 1, 101 overall form a combination actuator 200. The combination actuator 200 has effective gap regions 10 a, 10 b, 110 a, 110 bin which the contact portions 21, 31 of at least the one brake device 1 have a different structure than the component body 20, 30. In addition, the additional brake device 101 has effective gap regions 110 a, 110 bin which the contact section 121, 131 can be identical to the component body.The magnetic circuits of the two braking devices 1, 101 are separated from one another. That is, a magnetic field generating device 26 is provided for the effective gap areas with coating, for example, and a magnetic field generating device 126 (electric coil) is provided for the effective gap areas without coating, for example. The magnetic circuits can be controlled independently of one another.FIG. 2 cshows enlargements of the gap regions of different configurations. On the left, a cross section through the gap section 5 of a brake device 1 is depicted, wherein the inner brake component 2 forms a star contour radially on the outside. On the outside, a coating or the like is formed as a contact section 21, which for example selectively provides a higher hardness.In the middle of FIG. 2 c, a corresponding illustration of the gap section 105 of the additional brake device 101 is depicted, in which no separate contact sections 121, 131 are provided. The component bodies 120, 130 directly provide the contact surface 111, 112.The right-hand part of FIG. 2 cshows a variant in which the additional brake device 101 also has contact portions 121, 131, the (surface) nature of which differs from the nature of the material of the component body 120, 130. In this case, the characteristics and here the surface properties of the contact portions 21 and 121 and / or of the contact portions 31 and 131 are different. This also provides the braking devices 1, 101 with different braking properties, so that the device 100 can be controlled better overall.FIG. 2 d shows another variant in which the electrical coils 26, 126 are accommodated on the inner brake components 2, 102.FIGS. 3 and 4 show variations of contact sections which can optionally be provided only on one or both brake devices 1, 101. In any case, the brake devices 1, 101 differ, so that high braking torques are enabled on the one hand and good controllability is ensured on the other hand.FIG. 3 shows a cross section through the brake device 1. The inner brake component 2 can be seen on the inside, which is surrounded on the outside by the outer brake component 3. Between the brake components 2, 3 a gap section 5 is formed which extends all around here and which comprises the effective gap region 10 where the magnetic field 8 passes through the gap section 5. At least the effective gap region 10 is at least partially filled with a magnetorheological medium 6.The brake components 2, 3 each have a component body 20, 30. The outer brake component 3 is here formed cylindrically on the inside and on the outside and has a contact surface 12 on the inside. In the exemplary embodiment according to FIG. 3, the contact surface 12 is provided by a contact portion 31 which has different properties than the component body 30, and in the exemplary embodiment according to FIG. 3, the contact surface 11 is provided by a contact portion 21 which has different properties than the component body 20.The contact portions 21, 31 each have a higher hardness than the component bodies 20, 30. Further, the magnetic conductivity of the contact portions 21, 31 is respectively (significantly) lower than the magnetic conductivity of the component bodies 20, 30 (factor, 2 or 5 or 10 or more).In preferred configurations, at least one contact section is provided by a surface coating. The surface coating is preferably applied by a PVD or CVD method.Here, in FIG. 3, the (inner) brake component 2 has a non-round outer shape. The shape comprises "hills" and "valleys" therebetween. This shape can be referred to as a star contour, in which arms or teeth or elevations project radially outwards (star-shaped or helical). Overall, over the circumference of the effective gap region 10, a gap height that (here regularly) periodically changes arises.FIGS. 4a to 4e show variants as possible configurations. In FIG. 4 a, contact portions 21, 31 are respectively formed on the contact surfaces 11 and 12 to the effective gap. A (radial) thickness 31 aof the contact portion 31 is less than 1 / 5 or 1 / 10 or 1 / 50 of the (radial) wall thickness 30 aof the component body 30 (or the brake component 3). A (radial) thickness 21 aof the contact portion 21 is less than 1 / 5 or 1 / 10 or 1 / 50 or 1 / 100 of the diameter 20 aof the component body 20 (or the brake component 2), respectively.In the embodiment according to FIG. 4 a, the contact surfaces 11 and 12 are completely coated over the entire circumference or have contact portions 21, 31. Here, the contact portions 21, 31 are formed as layers and are applied as surface coatings 22, 32 to the component body 20, 30.In contrast to this, in the exemplary embodiment according to FIG. 4 b, only the radially outer contact surface 12 is equipped with a surface coating as contact section 31. The contact surface 11 of the inner brake component 2 here has no surface coating.In the embodiment of FIG. 4 c, it is reversed and a surface coating as the contact portion 21 is provided only on the component body 20 of the inner brake component 2.In the exemplary embodiment according to FIG. 4 d, the contact surface 12 (here the inner circumferential surface) of the brake component 3 is (completely) equipped with a contact section 31, while contact sections 21 are formed here only on the outer surfaces of the teeth (on the "hills") of the star contour of the inner brake component 2. On the tooth flanks and in the "valleys" between the "hills", no surface coating or contact portion 21 is provided. This portion of the contact surface is directly formed by a surface region 24 of the component body 21.Finally, in the example according to FIG. 4 e, contact portions 21 are only on a part of the contact surface 11, while no surface coating or contact portion 31 is formed on the contact surface 12. Here, a surface coating is formed only on the (radially) outer surfaces of the star contour. An arrow is drawn in dashed lines here by way of example onto a contact section 21, which can in principle also be embodied as a separate part 23 and can be pressed on or adhesively bonded on, for example.FIG. 5 shows another exemplary embodiment of a device 100 in which a linear actuator is used and in which two brake components 2, 3 are provided which are arranged so as to be longitudinally displaceable relative to one another and are part of a brake device 1. The device 100 may be, for example, a game controller or game pad or the like.If necessary, a second linear actuator 101 can be provided, which is arranged, for example, parallel behind the brake device 1 and is therefore not directly visible. It is also possible for two brake devices 1, 101 to be connected linearly one behind the other. In the exemplary embodiments according to FIGS. 5 and 6, two different brake devices 1, 101 can also be included.FIG. 6 shows a cross section through the brake device 1 of the device 100 from FIG. 5 ; the inner brake component 2 is accommodated in the outer brake component 3 in a longitudinally displaceable manner on the inside. The inner brake component 2 dips into a cavity of the outer brake component 3 and is prestressed into a basic position, for example, by a spring device 28 as a restoring spring. One type of piston rod 29 guides the inner brake component 2, which forms one type of piston 29 a, but does not pump a medium here.A gap 5 is formed between the two brake components 2, 3. The (complete) gap 5 is at least partially filled here with a magnetorheological medium 6 and overall forms an effective gap region 10.As FIG. 7 shows, on one or both brake components 2, 3 a contact section 21, 31 can be provided over the entire contact surface 11, 12 or even only over a part of the surface. In this respect, reference is made to the embodiments of FIGS. 4a to 4e. Corresponding configurations can also be realized here. A star contour can be formed in the axial direction, so that in the cross section according to FIG. 6, points with a larger and smaller diameter alternate in the axial direction.At the end of the gap 5 a sealing device 7 is provided (in particular each), which can be of conventional design or can comprise e.g. (also) a sealing unit with a magnet and a ferrofluid in order to seal the gap 5 at the end.The housing of the brake device 1 which surrounds the outer brake component 3 can in all cases consist, for example, of a plastic material.FIG. 8 shows a highly schematic illustration of a device 100 according to the invention, which comprises a combined actuator 200 with two separate brake devices 1 and 101. The brake devices 1 and 101 can operate linearly and / or rotatively and here have gap sections which are completely separated from one another.The brake devices 1 and 101 can also be arranged in parallel and connected to one another via, for example, a belt or a chain or the like in order to ensure simultaneous rotation in rotary brakes. The brake device 1 and the additional brake device 101 can be constructed as disclosed within the scope of this application.In principle, magnetically conductive parts have a relatively low hardness for physical reasons. The magnetorheological particles are also relatively soft. The brake components are also relatively soft and have a low carbon content because of the desired magnetic conducting properties.Preferably, a surface section limiting the effective gap region of a magnetorheological actuator (through which the magnetic field penetrates into the magnetorheological particles) is provided with a layer which is relatively hard-compared to the basic component of the brake component. This means that at least one section of a wall delimiting the effective gap region preferably has a hard layer, wherein the magnetorheological medium directly touches the hard layer in this contact section, in particular when the magnetic field is activated. The component body with good magnetic conductivity (the base component) on which the hard contact section (layer) is applied or formed is not in contact with the magnetorheological medium due to the hard contact section (there). The use is possible in rotary actuators and also in linear actuators.It is surprising that improved properties are provided when forming a contact section that is harder, for example compared to the component body, since firstly a deterioration in the performance (maximum torque for the same coil current) would be assumed. Hard materials generally result in a (relative) reduction in the coefficients of static friction. It would therefore be expected that less friction and thus also a lower "wedge effect" will be produced at the boundary layer between the magnetorheological particles and a brake component. In addition, the magnetic conductivity is reduced by the harder contact section (coating / curing), whereby the amount of the magnetic field in the effective gap is reduced with the same coil current. This also reduces the effect in principle. However, it has been found that, perhaps by a lower flexibility of the surfaces, such effects are more than compensated for and an effect ratio (maximum / minimum effect) is improved.In principle, substantially all boundary surfaces of the gap or in particular of the effective gap region could have a (harder) contact section in the form of a harder layer, for example. When, for example, a non-round contour (star contour) and an opposite wall (inner wall) are used, all surfaces in the effective gap region can be coated. In addition, the end faces of the inner brake component can also be coated, although there is generally no magnetic field. A harder contact layer can also be advantageous and applied in one operation. Furthermore, wear is reduced and tightness is improved if coating is also carried out in the region of the sealing devices as a sealing seat.In a rotary actuator, an electric coil device can also be arranged on the outer brake component. In all embodiments, the magnetic field of the magnetic field generating device runs through the brake components and the effective gap region of the gap.List of reference numbers:1 Magnetorheological brake device 2 (inner) brake component 3 (outer) brake component 4 housing 5 gap section 6 medium 7 sealing device 8 magnetic field 9 bearing unit 10 effective gap region, effective gap section 10 aactive gap region 10 bactive gap region 11 contact surface 12 contact surface 20 component body 20 athickness 21 contact section 21 athickness 22 surface coating 23 separate part 24 surface region 26 magnetic field generating device 26 acoil device 27 cable 28 spring device 29 piston rod 29 apiston 30 component body 30 athickness 31 contact section 31 athickness 32 surface coating 100 device 101 magnetorheological additional brake device 102 brake component 103 brake component 105 gap section 108 magnetic field 110 effective gap region, Effective gap portion 110 a Gap portion 110 b Gap portion 111 Contact surface 112 Contact surface 120 Component body 121 Contact portion 126 Magnetic field generator 130 Component body 131 Contact portion 140 Separator 150 Separator 200 Combination actuator

Claims

Device (100) comprising at least one magnetorheological brake device (1) with at least two brake components (2, 3) movable relative to each other and each having a component body (20, 30) and with at least one magnetic field generating device (26) for generating a magnetic field, wherein a gap section (5) is formed between the brake components (2, 3) and comprises at least one effective gap region (10) equipped with a magnetorheological medium (6), wherein the magnetic field of the magnetic field generating device (26) runs through the component bodies (20, 30) of the brake components (2, 3) and passes through the effective gap region (10) in order to influence the magnetorheological medium (6) and thus a relative movability of the two brake components (2, 3) relative to each other, wherein one of the brake components (2) is formed as an inner brake component and the other brake component (3) is formed as an outer brake component, characterized in that at least one brake component (2, 2, The contact portion (21, 31) adjoining the effective gap region (10) and having a different structure from the component body (20, 30).The device (100) according to the preceding claim, wherein the contact portion (21, 31) has a higher hardness than the material of the component body (20, 30) and wherein the contact portion (21, 31) has a better sliding quality than it would have an identically structured surface made of the material of the component body (20, 30) and wherein the contact portion (21, 31) has a lower magnetic conductivity than the material of the component body (20, 30).The device (100) according to any one of the preceding claims, wherein the contact portion (21, 31) comprises at least one layer from a group of layers comprising layers of titanium nitride, titanium aluminum nitrite, titanium carbon nitrite, titanium aluminum carbonitride, titanium carbide, titanium carbonite layers and amorphous carbon layers.Device (100) according to one of the preceding claims, wherein both brake components (2, 3) each have at least one contact section (21, 31) with a different nature from the respective component body (20, 30).The device (100) according to any one of the preceding claims, wherein at least a part of the effective gap region (10) has a periodically variable effective gap height (13).Device (100) according to one of the preceding claims, comprising a magnetorheological auxiliary braking device (101) having two braking components (102, 103) which can be moved relative to one another and each have a component body (120, 130) and having at least one (additional) magnetic field generating device (126) for generating a magnetic field (108), wherein an (additional) gap section (105) is formed between the braking components (102, 103) and comprises at least one (additional) effective gap region (110a) which is equipped with a magnetorheological medium (6), wherein the magnetic field of the (additional) magnetic field generating device (126) runs through the component bodies (120, 130) of the braking components (102, 103) of the auxiliary braking device (101) and passes through the (additional) effective gap region (10a) in order to provide the magnetorheological medium (6) and thus a relative movability of the two braking components (102, 102, 103) of the additional brake device (101) relative to each other.The device (100) according to the preceding claim, wherein a typical condition of a contact surface of the magnetorheological brake device (1) differs (significantly) from a typical condition of a contact surface of the magnetorheological auxiliary brake device (101).Device (100) according to one of the two preceding claims, wherein one of the brake components (2) of the additional brake device (101) is designed as an inner brake component (102) and the other brake component (103) is designed as an outer brake component of the additional brake device (101).The device (100) according to one of the three preceding claims, wherein at least one brake component (102, 103) of the additional brake device (101) comprises a contact section (121, 131) of the additional brake device (101) adjoining the (additional) effective gap region (110), with a different nature from the component body (120, 130) of the additional brake device (101).Device (100) according to one of the four preceding claims, wherein the braking device (1) has a lower braking capacity (force / torque) than the additional braking device (101).The device (100) according to any one of the five preceding claims, wherein the gap section (5) of the braking device (1) and the gap section (105) of the additional braking device (101) are formed at least partially at a common gap and / or wherein the gap section (5) of the braking device (1) and the gap section (105) of the additional braking device (101) are formed at least partially at different gaps and separate from one another.Device (100) according to one of the six preceding claims, wherein the braking device (1) and the additional braking device (101) are designed as separate actuators.The device (100) according to any one of the seven preceding claims, wherein the contact portion of the braking device (1) and the contact portion of the supplementary braking device (101) differ in at least one property (texture) of their surface from a group of properties (textures) comprising the roughness, the polishing degree, the static friction coefficient, the sliding friction coefficient, the material composition and the hardness.The device (100) according to any one of the eight preceding claims, wherein the component bodies (120, 130) of the auxiliary brake device (101) form the contact surfaces (directly).

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