STEERING DEVICE WITH A MAGNETORHEOLOGICAL BRAKING DEVICE AND METHOD FOR OPERATING A STEERING DEVICE

Abstract

A steering device with a movable steering unit. A movement of the steering unit can be braked by a magnetorheological braking device. The braking device has a stationary holder and two brake components. One brake component can be rotated by the steering unit. One brake component is connected to the holder for conjoint rotation. The two brake components can continuously rotate relative to one another about an axis. A first brake component extends along the axis and has a magnetically conductive core. The second brake component has a casing part around the first brake component. A gap between the first and second brake component is filled with a magnetorheological medium. The gap has two brake gap portions. A disk contour is formed between the casing part and core in a first brake gap portion, and a different disk contour is formed between the casing part and core in a second brake gap portion.

Claims

1-39. (canceled)

40. A steering device for steering a vehicle comprising: a movable steering unit, a movement of the steering unit being configured to be braked by at least one magnetorheological braking device; the braking device having a stationary holder and at least two brake components; at least one of the at least two brake components being rotatable by the steering unit and at least one other of the two brake components being non-rotatably connected to the holder; the at least two brake components being continuously rotatable relative to one another about an axis of rotation; a first brake component of the at least two brake components extending along the axis of rotation and having a core made of a magnetically conductive material; a second brake component of the at least two brake components having a hollow casing part extending around the first brake component; at least one circumferential gap filled at least partially with a magnetorheological medium being formed between the first and second brake component; the at least one circumferential gap having a plurality of brake gap sections, being at least three brake gap sections or at least two differently shaped braking gap sections; a disk contour being formed between the casing part and the core in a first braking gap section of the at least three brake gap sections; and a differently shaped disk contour being formed between the casing part and the core in a second braking gap section of the at least three brake gap sections.

41. The steering device according to claim 40, wherein: at least one third brake gap section of the at least three brake gap sections is arranged axially between the first brake gap section and the second brake gap section; and the first brake gap section has a first electric coil and the second brake gap section has a separately controllable second electrical coil.

42. The steering device according to claim 40, further comprising at least one drive device for generating a drive torque for the active movement of the steering unit, the drive device having at least one electric motor arranged at least substantially radially within an outer circumference of the gap.

43. The steering device according to claim 40, further comprising an actuator configured for converting a steering movement carried out with the steering unit into a vehicle movement, wherein the steering unit and the actuator are configured to be operatively connected electrically and/or electromagnetically.

44. The steering device according to claim 40, wherein the braking device has a braking torque when the magnetorheological medium is actively influenced and a basic torque when the magnetorheological medium is influenced in an inactive manner, and the basic torque increases by at least a factor 50 less than a maximum braking torque that can be provided.

45. The steering device according to claim 40, wherein the first brake gap section is assigned a first electrical coil and the second brake gap section is assigned a separately controllable second electrical coil.

46. The steering device according to claim 40, comprising at least one steering control unit for controlling the braking device depending on a position of the steering unit and/or a movement parameter of the steering unit and/or an operating state of the vehicle, and wherein the at least two brake gap sections can be controlled separately by the steering control unit.

47. The steering device according to claim 46, wherein the steering control unit is configured to select at least one brake gap section of the at least two brake gap sections depending on the level of a braking torque to be set and/or at least to combine two of the braking gap sections and thus to brake the movement of the steering unit.

48. The steering device according to claim 46, wherein the steering control unit is configured to generate a braking torque for braking the movement of the steering unit at least predominantly with the first braking gap section if the vehicle speed is above a limit value.

49. The steering device according to claim 46, wherein the steering control unit is configured to block mobility of the steering unit and the only with the second brake gap section and/or or with a combination of at least two braking gap sections is configured to provide a braking torque required to block mobility of the steering unit.

50. The steering device according to claim 46, wherein the steering control unit is configured to have an end stop for the mobility of the steering unit at least predominantly provided by the second brake gap section and/or with a combination of at least two brake gap sections.

51. The steering device according to claim 46, wherein the steering control unit is configured: to brake or block mobility of the steering unit as a function of a driver assistance system to prevent critical steering movements; and to select at least one braking gap section of the at least two braking gap sections to control the braking or blocking.

52. The steering device according to claim 47, wherein the steering control unit is configured to take into account a user property for setting the braking torque.

53. The steering device according to claim 47, wherein the steering control unit is configured to adjust the braking torque based on the position at which the steering unit is held.

54. The steering device according to claim 46, wherein the steering control unit is configured to generate a haptically perceptible feedback on the steering unit with a defined sequence of braking torques.

55. The steering device according to claim 46, wherein the steering control unit is configured to determine user behavior using at least one algorithm of machine learning and to setting the braking torque based on the determined user behavior.

56. The steering device according to claim 40, wherein the magnetorheological medium has at least one metallic powder and wherein the metallic powder has a volume fraction of at least 50%.

57. The steering device according to claim 56, wherein the metallic powder is provided with a coating.

58. The steering device according to claim 40, further comprising at least one retentivity device and/or at least one permanent magnet unit which is configured to maintain a braking torque with at least one of the at least two brake gap sections without the supply of electric current.

59. The steering device according to claim 40, further comprising at least one safety device configured to remove the magnetorheological medium at least partially from the gap.

60. The steering device according to claim 40, wherein the gap has a maximum diameter of less than 100 mm.

61. The steering device according to claim 40, further comprising at least one drive device configured for generating a drive torque for actively moving the steering unit.

62. The steering device according to claim 61, wherein a maximum braking torque of the second brake gap section is at least twice a maximum drive torque of the drive device.

63. The steering device according to claim 61, wherein the braking device, in the event of a failure of the drive device, can provide a braking torque which is at least as high as its drive torque.

64. The steering device according to claim 61, wherein the steering control unit is configured to at least approximately compensate for fluctuations in the drive torque of the drive device by adjusting the braking torque.

65. The steering device according to claim 40, wherein the disk contour has at least one star contour, and, in the area of the star contour, a variable gap height over the circumference of the braking gap section, and wherein magnetic field concentrators are arranged on the star contour and protrude radially into the braking gap section.

66. The steering device according to claim 41, wherein the first electrical coil and the second electrical coil are each received between the casing part and the core and are each wound around the axis of rotation.

67. The steering device according to claim 41, wherein the first electric coil and the second electric coil are designed differently and wherein the first electric coil and the second electric coil are in at least one Distinguish parameters from a group of parameters, which group includes as parameters the wire diameter and wire cross-section, the number of windings, the winding window, the type of winding, the coil width, the coil diameter and the material.

68. The steering device according to claim 40, wherein the third braking gap portion is formed through at least one ring contour, which is arranged between the casing part and the core.

69. The steering device according to claim 68, wherein the first electrical coil is arranged axially between the first brake gap section and the ring contour and wherein the second electrical coil is arranged axially between the ring contour and the second brake gap section.

70. The steering device according to claim 68, wherein the ring contour is designed as a separate part and wherein the magnetic fields of the first electric coil and the second electric coil run through the ring contour.

71. The steering device according to claim 40, further comprising: a sensor configured for detecting a relative angle of rotation between the core and the casing part; and/or a sensor for detecting a relative axial position of the casing part to the brake component.

72. The steering device according to claim 40, wherein the magnetorheological medium contains individual magnetically polarizable particles; and a magnetic field strength between the individual magnetically polarizable particles is greater than 300 kA/m.

73. The steering device according to claim 40, wherein a magnetic field strength that can be generated in the gap is greater than 500 kA/m.

74. The steering device according to claim 40, wherein the at least three brake gap sections is at least four brake gap sections.

75. The steering device according to claim 40, wherein the at least one magnetorheological braking device is at least two magnetorheological braking devices.

76. A Method for operating a steering device, the method comprising: providing a magnetorheological braking device with two braking components, the two braking components being continuously rotatable about an axis of rotation relative to one another, with a first braking component extending along the axis of rotation and having a core made of a magnetically conductive material, and the second brake component having a casing part extending around the first brake component, and at least three circumferential brake gap sections are formed between the first and the second brake component which are axially spaced apart from one another and at least partially filled with a magnetorheological medium; generating, with a first electric coil, a controlled magnetic field in a first and a third braking gap section; and generating, independently, with a second electric coil, a controlled magnetic field in a second and the third brake gap section in order to generate braking effects of different strength depending on the speed.

77. The method according to claim 76, wherein different fast braking effects are generated with the first electric coil and the second electric coil.

78. The method according to claim 76, wherein braking effects of different energy efficiency are generated with the first electric coil and the second electric coil.

Description

[0133] Show in it:

[0134] FIG. 1 is a purely schematic representation of a steering device according to the invention with a magneto-rheological braking device's;

[0135] FIG. 2 shows a side view of a braking device;

[0136] FIGS. 3a-3c different sections of braking devices;

[0137] FIGS. 4a-4b is a highly schematic view of a sensor device and measurement results;

[0138] FIG. 5 is a highly schematic view of a braking devices with a snap disk in different positions;

[0139] FIG. 6 two differently designed electrical coils;

[0140] FIGS. 7a-7b another haptic braking device in section and in perspective;

[0141] FIG. 8 is a schematic cross section of another braking device 1;

[0142] FIG. 9 shows a highly schematic circuit for controlling the electrical coil;

[0143] FIG. 10 a sketch with braking torque curves to illustrate the functioning of the braking device; and

[0144] FIG. 11 shows another sketch with braking torque curves.

[0145] FIG. 1 shows a steering device 100 according to the invention for steering a vehicle, not shown in detail here, by means of a steering unit 301. The steering unit 101 is designed here as a rotatable steering wheel which is connected to a steering shaft in a rotationally fixed manner.

[0146] The steering device 100 is here as a steer-by-wire steering system educated. An actuator device 303 is used for this purpose to convert the steering movement carried out with the steering unit 301 into a vehicle movement. For example, the actuator device 303 steers the vehicle wheel or wheels. Actuator device 303 is only electrically connected to steering unit 101.

[0147] The rotational movement of the steering unit is detected by means of a sensor device 70 and, for example, a rotational angle sensor. Depending on the angle of rotation, the actuator device 303 then steers e.g., the vehicle wheel or wheels. It can thus e.g., the front and/or the rear wheels are steered or in a tricycle the tilt of the tricycle. It can also be used to steer the wheels of the front axle and rear axle or even all axles (so-called crab steering).

[0148] A drive device 307 designed as an electric motor is connected to the steering shaft 311 here. The steering unit 301 can be actively rotated by the drive device 307. As a result, the steering unit 301 is actively moved, for example when cornering, as would also be the case with a conventional mechanical steering system.

[0149] The movement of the steering unit 101 can be braked in a targeted manner by means of a magnetorheological braking device 1. To control the braking device 1 and also the drive device 307 depending on various parameters and e.g., the steering angle, a steering control unit 302 is provided here. For this purpose, the steering control unit 302 is operatively connected to the sensor device 70.

[0150] The steering control unit 302 also takes into account, for example, data from a driver assistance system 304. As a result, the movement of the steering unit 301 can be influenced in a targeted manner depending on the driving situation. The steering control unit 302 can also be operatively connected to other sensors, not shown in detail here, in order to Being able to specifically influence steering behavior as a function of other parameters.

[0151] The braking device 1 is equipped here with a safety device 306 which removes a magnetorheological medium 6 (not visible here) from a gap 5 (also not visible here). In the event of a fault, for example, the braking torque can be canceled very quickly and reliably. The gap 5 and the medium 6 are presented in more detail with reference to the following figures.

[0152] FIG. 2 shows a side view of a brake device 1 with a holder 4 which can be fastened to a bracket 50, for example, via a nut 51. The braking device 1 has two braking components 2, 3, of which the inner braking component 2 is not visible in FIG. 2. The inner brake component 2 is connected to the holder 4. The holder 4 and the inner brake component 2 are designed to be stationary here. The other brake component 3 includes the casing part 13 and is rotatably accommodated on the first brake component 2.

[0153] The braking device 1 has a compact design and inside the shielding device 75, which has a two-part shielding body 76 as a shielding housing, has a sensor device 70 (not visible here) for detecting the rotational position and the axial position of the casing part 13. The casing part is connected via pins 16 13 is connected to a left lid 14 and a right lid 15 to seal an inner closed chamber 110.

[0154] Shown in the FIGS. 3a to 3c are possible cross sections of a braking device 1 e.g., from FIG. 2. Mounted on the bracket 4 is the brake component 2 extending in the axial direction and to which the core 21 is fixed. The core 21 is surrounded radially by the (magnetically conductive) casing part 13 as the outer or second brake component 3.

[0155] The magnetically conductive core 21 is made up of two electric coils 26, which are wound around the core 21. The first electric coil 261 extends over an axial width 26e. At the end of the core 21 facing the holder 4, a disk contour 41 is formed, which is applied here to the core and e.g., is pressed. For this purpose, the disk contour 41 has a disk body 42 of hollow-cylindrical design. The receptacle on the core can also be non-round.

[0156] In particular, the core 21 can be made of sintered material (metal). The core can thus be manufactured more easily in the desired shape.

[0157] The disk body 42 consists here of a disk pack 44 which is formed by a plurality of thin disk plates 46. Here, the sheet metal disks 46 are each formed as a stamped part and can be stamped out, for example, from a magnetically conductive sheet metal with a thickness of 1 mm or 2 mm or even 3 mm. In this way, the required number of sheet metal panes can be punched out easily and inexpensively in order to produce the desired thickness of the pane body 42.

[0158] The individual disc plates 46 are pressed together and applied to the core 21 and thus, for example, screwed or pressed. A braking gap section 5a remains in the area of the disc body 42 with a small gap height 41b between the outer diameter of the disc contour 41 and the inner circumference of the casing part 13. The axial width 41e of the disc contour 41 or its braking gap section 5a is determined here by the number of disc laminations 46 and can be larger or smaller than shown.

[0159] Here, the disc contour 41 is axially directly adjacent to the first electrical coil 261, which is accommodated in a coil holder 26b and is completely sealed radially on the outside by a casting compound 28.

[0160] The disc body 42 is connected to the core 21 and the fixed brake component 2 and rotates in the operation not. This enables a hole or recess to be formed for the cables 45 to be fed through for the electrical connection of the first and second electrical coils 261, 262. The electrical coils 261, 262 can thereby be connected simply, inexpensively and quickly.

[0161] The disk contour 41 is formed here at the proximal end, that is to say at the end of the core 21 which faces the holder 4. At the distal end, i.e., at the other end of the core 21, a second braking gap portion 5b is formed. The second brake gap section 5b extends over an axial width 11e. A disc contour 41 is also arranged there, which is shaped analogously or identically to the disc contour 41 of the proximal end in terms of its geometry. But it is also possible that the disc contour 41 is shaped differently than the disc contour 41 of the proximal end and e.g., in the gap height or in the degree of change in the gap height (a star contour 40) differs. In contrast to the disk contour 41 of the proximal end, the disk contour 41 is formed here (circumferentially) in one piece with the core, as is shown schematically in the lower part of FIG. 3b. However, the disk contour 41 can comprise a (circulating) disk package with a plurality of disk plates 46.

[0162] The second braking gap section 5b allows a very high braking torque to be achieved with the second electrical coil 262, in particular at low speeds of rotation of the casing part 13. Through the first brake gap section 5a in the area of the disc contour 41, a still strong magnetic field can be transmitted from the core 21 to the casing part 13 with the first electrical coil 261 at high speeds, since the gap height 41b is considerably smaller than the radial free space 11c in the area whose brake gap section is 5b. As a result, a high torque can be generated, which is also made possible, in particular, at higher speeds. As a result, through targeted and separate activation of the two electric coils 261, 262 a high and finely adjustable torque can be made available over the entire speed range.

[0163] The axial width 11e of the second brake gap section 5b and the width 41e of the first brake gap section 5a are approximately the same here (+/?25%) and each shorter than an axial width of the third brake gap section 5c. Overall, a very compact structure is achieved.

[0164] The casing part (jacket part) 13 is surrounded by a coating 49 as a rotary knob 23 in FIG. 3a. The knob 23 is at least partially transparent so that it can be illuminated by the lighting means 18 in the form of LEDs, for example. The lighting can be controlled depending on the situation or independently of the situation. This design is primarily intended for steering devices for computer games, but can also be used to advantage in vehicles.

[0165] At the front end, the closed chamber 110 inside the casing part 13 is closed off by a front cover 14 through which the brake component 2 is passed. A seal 38 is used for sealing. At the rear or distal end, the chamber 110 is initially delimited by an elastic membrane 31, which is adjoined to the outside by a click element 29 designed here as a snap-action disk.

[0166] The second coil 262 or the associated core material is also designed here as a remanence device 305. If the retentivity device 305 was previously activated, a magnetic field that influences the medium 6 and thus maintains a braking torque remains even after the power supply has been switched off. For example, a steering wheel lock can be enabled without additional power consumption. A parked vehicle should consume as little electricity as possible, preferably none at all, otherwise the battery could be drained (both in vehicles with a combustion engine and in electrically powered vehicles). The steering wheel lock should therefore also switch on when it is not powered apply high locking torque. A remanence device can provide this.

[0167] FIG. 3b shows a slightly different representation of a braking device 1, in which case, in contrast to FIG. 3a, the cover 49 or the rotary knob 23 has been omitted.

[0168] An essential difference between FIGS. 3a and 3b is that in FIG. 3b the first braking gap section 5a with the disk contour 41 is provided at the distal end of the casing part 13, while the second braking gap section 5b is provided at the proximal end of the casing part 13.

[0169] In this configuration, for example, outside of chamber 110 between seal 38 and sensor device 70 there can also be a bearing for mounting jacket part 13 with respect to brake component 2. However, it is also possible here for the bearing to take place at one end only via the seal 38 and at the other distal end only via the disk contour 41.

[0170] The disk contour 41 can be formed (circumferentially) in one piece with the core, as is shown schematically in the lower part of FIG. 3b. Or the disk contour 41 comprises a (circular) disk pack with a plurality of disk plates 46, as is shown by way of example in the upper part of FIG. 3b. The disk contour can also be placed on the core as a solid separate part, that is to say it can practically consist of a single disk sheet of correspondingly greater thickness.

[0171] Some magnetic field lines 8 of the first electric coil 261 and the second electric coil 262 are drawn in as an example in FIG. 3b. Furthermore, it can also be seen that in each case an (approximately) radial passage of the magnetic field lines 8 takes place in the braking gap sections 5a and 5b. In the braking gap portion 5a, at higher speeds, a higher

[0172] Torque generated while in the braking gap portion 5b at higher torque is generated at lower speeds. The respective magnetic field is closed in each case in the central area by the (roughly) radial transition to the third brake gap section 5c. There is practically a thin gap at the braking gap section 5c, similar to the first braking gap section if a cylindrical disk contour 41 is used there.

[0173] The magnetic field sensor 72 is mounted on a sensor circuit board 79 and can be contacted via the contact pins 79a. The electrical coil 26 is also supplied with current via this.

[0174] At least in the area of sensor device 70 and magnetic field sensor 72, inner braking component 2 is preferably made of a material that is not magnetically conductive or has little or no magnetic conductivity, in order to enable detection of the orientation and intensity of the magnetic field of magnetic ring unit 71 in the interior of axle 12 or the to ensure first brake component 2. The sensor device 70 is accommodated there in a particularly protected manner (protection from water and dust).

[0175] An O-ring 39 can be seen in FIG. 3b which seals the cover 14 against the casing part 13.

[0176] The third braking gap section 5c is formed on the ring contour 61. The ring contour 61 can be slid onto or attached to the core 21 as a separate ring, or the ring contour 61 is formed in one piece with the core 21. In any case, the ring contour 61 is coupled to the core 21 in a magnetically conductive manner.

[0177] In a purely schematic manner, the top half of FIG. 3b shows an alternative embodiment in which a fourth braking gap section 5d is integrated. The fourth brake gap section 5d can, for example, arise from the fact that the annular contour 61 provides two separate braking gap sections 5c and 5d. For example, two magnetically conductive ring parts can be included, which are separated from one another by a magnetically less conductive intermediate part or ring part 61a. then two axially separate brake gap sections 5c and 5d are formed. In other configurations, the electrical coils 261, 262 and the brake gap sections 5c, 5d can also be arranged further apart from one another, so that two magnetic circuits which are further separated from one another are produced.

[0178] A structure with three braking gap sections, with the central braking gap section 5c being provided for both electrical coils 261, 262, enables a particularly compact structure.

[0179] A structure as shown in FIG. 3a or 3b provides an advantageous embodiment. The second electrical coil 262 enables a particularly strong braking torque in the second brake gap section 5b via the rolling elements 11, in particular at low speeds or at a standstill. At higher speeds, the first electrical coil 261 enables a high braking torque via the very small gap height in the first braking gap section 5a.

[0180] If a rotational movement is to be braked and a stop is to be made available, the first electric coil 261 on the first brake gap section 5a enables greater braking at higher speeds than the second electric coil 262 on the second brake gap section 5b. At a relatively low transition speed, the braking torque that can be generated with the second electric coil 262 in the second brake gap section 5b becomes greater than the braking torque that can be generated in the first brake gap section 5a at this speed. Optimum conditions can thus be set for different speeds via a combination of specifically different braking gap sections 5a, 5b.

[0181] A magnetorheological medium which comprises magnetorheological particles 19 is accommodated in the chamber 110. A gap 5 is provided in the chamber 110 between the brake components 2 and 3. At the gap 5, the three braking gap sections 5a, 5b and 5c are formed. Chamber 110 is at least partially filled with a magnetorheological medium 6 here. The medium here is preferably a magnetorheological fluid which, for example, comprises an oil as the carrier liquid, in which ferromagnetic particles 19 are present. Glycol, grease, water and viscous materials can also be used as a carrier medium, but are not limited to them. The carrier medium can also be gaseous or the carrier medium can be dispensed with (vacuum). In this case, only particles 19 that can be influenced by the magnetic field are filled into the chamber 110.

[0182] The ferromagnetic particles 19 are preferably carbonyl iron powder, with the size distribution of the particles depending on the specific application. A particle size distribution of between one and ten micrometers is specifically preferred, although larger particles of twenty, thirty, forty and fifty micrometers are also possible. Depending on the application, the particle size can also become significantly larger and even reach the millimeter range (particle balls). The particles can also have a special coating/shell (titanium coating, ceramic, carbon shell, etc.) so that they can better withstand the high pressure loads that occur depending on the application. For this application, the magnetorheological particles can be made not only of carbonyl iron powder (pure iron), but e.g., can also be made of special iron (harder steel).

[0183] It is possible that only particles that can be influenced by the magnetic field are filled into the gap 5 or the chamber 110, with air or an inert gas being added if necessary. if e.g., only air or another gas is used, different solids can be mixed to improve certain properties. For example, graphite powder can be admixed to reduce the friction between the carbonyl iron particles since graphite has a lubricating effect. The particles can in particular with PTFE be coated. In particular, a coating with PTFE or a comparable coating prevents the particles from clumping together and forming larger heaps. Such larger heaps do not disintegrate easily or may not disintegrate at all. Alternatively, the disk bodies or roller bodies can be coated with PTFE to reduce friction. When using MRF without oil or other liquid as a carrier medium, it must be ensured that no water condenses in the brake chamber (MR space or MRF space). For example, silicic acid gel (known as silica gel) or another desiccant that absorbs water and thus removes moisture from its surroundings can be mixed in.

[0184] If powder is used without a carrier liquid, up to about 80 percent by volume of carbonyl iron (iron powder) is possible, which greatly increases the braking torque if the remaining design parameters are adjusted accordingly (e.g. the field strength per particle should remain the same as with a magnetorheological fluid (MRF), i.e. the field strength in the braking gap or active gap should be twice as high when changing from, for example, LORD MRF 140 (40 percent by volume carbonyl iron with e.g. oil as the carrier liquid) to 80% carbonyl iron powder (without carrier liquid). We are talking about magnetic field strength in the gap of greater 200 kA/m up to values of up to 1,000 kA/m (1000000 A/m) or more. Another advantage of powder as a medium in the active gap is that there is no sedimentation and no accumulation in the sense of the iron particles MR liquids are pulled in the direction of the magnetic field gradient (the force on magnetizable particles always acts in R direction of the stronger magnetic field, the carrier medium is displaced) must come in order to obtain such high particle concentrations. The maximum particle concentration is already there. This improves the reproducibility of the torques (a similar braking torque always occurs with the same current).

[0185] In all configurations, it is particularly preferred that the Magnetic polarizable particles (to a significant extent) include non-round particles (non-spherical particles) in which a ratio of the largest diameter to the largest transverse extension perpendicular thereto is greater than 1.25 or 1.5. It is also possible to form this ratio as a ratio of the greatest longitudinal extent to the greatest transverse extent, with the longitudinal and transverse extents in particular being measured perpendicular to one another.

[0186] The use of out-of-round particles is particularly advantageous since they enable an effective canting structure, since different out-of-round sections of the particles jam or wedge with one another.

[0187] Ratios of the largest diameter to the largest transverse extension perpendicular thereto of 1.75 or 2.0 or more are also possible and preferred.

[0188] At least some of the magnetically polarizable particles are preferably designed to clamp or wedge together over a large area under the influence of the magnetic field. This is possible, for example, with particles that are angular in sections or, for example, are triangular or polygonal overall or the like. Two (or more) correspondingly configured particles then jam together and can cause the particles to clump together very effectively and cause the two brake or clutch components to jam and brake together.

[0189] At least some of the magnetically polarizable particles are preferably designed to clamp or wedge together under the influence of the magnetic field at two or more locations spaced apart from one another. Particles of this type, which are non-round, permit a very effective increase in the braking force or the braking moment, since, in contrast to spherical particles, they do not only touch at one point or in a small angular range, but rather at several points or even flat.

[0190] Preferably, at least some of the magnetically polarizable particles have at least one trough section. Such an inwardly curved trough section allows particularly effective wedging with parts of other particles.

[0191] Preferably, at least one surface of at least one clutch or brake component adjoining the brake gap is designed to be non-smooth or (locally) uneven at least in sections. It is also possible that the particles or a significant part of the magnetically polarizable particles have elevations or elevations and/or depressions regularly or irregularly on the outer surface. As a result, canting with the particles can be reinforced. For example, at least one surface can have elevations and/or depressions in the manner of pointed or rounded dimples in golf balls. A surface with a pointed or rounded sawtooth profile is also possible. A relative height (at least some) of the peaks or valleys is preferably at least 5% or 10% of the minimum diameter of a magnetically polarizable particle.

[0192] It has been found that a particularly effective canting and jamming of individual particles can be generated with high magnetic field strengths. For this purpose, a magnetic field strength of greater than 150 kiloamperes/meter (kA/m) or of 250 kiloamperes/meter or 500 kA/m or more is preferably generated in the gap. In particular, a magnetic field strength greater than 500 kiloamperes/meter (kA/m) or 750 kiloamperes/meter or 1000 kA/m or more can be generated or is generated in the gap, preferably in at least one of the braking gap sections.

[0193] If only powder without liquid carrier medium is used, a different type of seal can be selected and the basic friction thereby be reduced. The seal does not have to be pressed as hard against the surfaces, since it is not necessary to seal for liquids, only particles. A non-contact shaft seal such as a labyrinth seal can also be used, for example. This type of seal only rests on one of the two mutually rotating parts. In addition, the temperature dependence is reduced or almost eliminated. Liquid carrier media change their viscosity with changing temperatures, while carbonyl iron powder hardly changes its properties in very large temperature ranges (until the Curie temperature is reached). The temperature-related volume change is also negligible for powder, since the particles can redistribute among themselves if the volume of the individual particles changes.

[0194] The maximum volume fraction of carbonyl iron particles in powder form (approx. 74%) is also higher than in MRF with e.g., oil as a carrier medium.

[0195] The magnetorheological particles 19 chain together when a magnetic field is applied, as shown very schematically on the left in FIG. 3c. This creates a wedge effect, which leads to a significant increase in the braking torque at low and medium speeds.

[0196] For a more detailed explanation of this effect, reference is made to FIG. 4 of the applicant's international application WO 2018/215350 A1, which, with regard to the explanation of the effect, is fully included in the scope of disclosure of this application in an adapted manner.

[0197] FIG. 3c shows basically schematic cross sections of the braking gap sections 5a and 5b and 5c. A cross section through the first or also the third brake gap section 5a, 5c in the area of the disc contour 41 is shown on the right in FIG. 3c. The disc contour 41 provides a disc body 42, which here rests on the core 21 is applied or is integrally formed as an annular flange on it. Radially on the outside between the outer contour of the disk contour 41 and the inner circumference of the casing part 13 there is a gap height 41b which is considerably smaller and can be chosen to be considerably smaller than the radial free space 11c in the second brake gap section 5b. The disc body 42 can be solid or can be designed as a disc pack 44 and include a plurality of disc plates 46. The first and the third braking gap section 5a, 5c can in principle have identical or similar cross sections.

[0198] A rolling body 11 is shown in dashed lines in the right-hand part of FIG. 3c, just as an example, in order to clarify the differences. It can be clearly seen that the disc body 42 allows a gap height 41b with a smaller height. As a result, a strong braking torque and a high magnetic field strength can be achieved and transmitted there. A desired magnetic field strength and braking effect can be set independently via the other electric coil in the second brake gap section 5b. Both magnetic fields are closed via the third brake gap section 5c.

[0199] A cross section of a further embodiment of a brake gap section is shown on the left in FIG. 3c. This braking gap section has a disk contour 41 designed as a star contour 40. The star contour 40 has a non-round peripheral surface. This creates a braking gap section with a variable gap height 40c over the circumference. This can also result in a kind of wedge effect and a high torque can be set, especially at low speeds. The elements projecting radially outward (or inward) can be referred to as magnetic field concentrators 80, which locally concentrate the magnetic field. A star contour 40 can also be in the form of a disk assembly 44 and can include a plurality of (e.g. star-shaped) sheet metal disks 46.

[0200] A star contour can also be formed in the axial direction this means that variable gap heights occur in the axial direction. As a result, the magnetic field can be concentrated in the axial direction at locations with a lower gap height and reduced in the higher gaps. A mixture of radial and axial and/or oblique star contours is also conceivable.

[0201] In particular, this configuration is suitable for the second braking gap section 5b as a replacement for a (second) braking gap section (5b) with rolling bodies.

[0202] The sensor device 70 is shown in detail in FIG. 4. The first brake component 2 and the second brake component 3 embodied here as a casing part 13 are only indicated (dashed lines). The sensor device 70 is supported in a magnetically decoupled manner via the decoupling device 78 on the rotatable second brake component. The shielding device 75 here consists of three shielding bodies 76 which reduce the scattering of the magnetic field 8 of the electrical coil 26. The shielding device 75 can also only consist of pot-shaped bodies or a pot-shaped body and a disc-shaped body that are connected to one another.

[0203] In addition, there is also a separating unit 77 for magnetic separation. The magnetic ring unit 71 is used to measure the orientation or the angle of rotation s of the magnetorheological braking device 1's is used. The magnetic field sensor 72 is arranged inside the first brake component 2, which is non-magnetic in this area. Small relative axial displacements, such as those caused by actuating a snap-action disk, for example, can be used to detect the actuation of the control button 101, as shown in FIG. 4b. The angle of rotation and the orientation of the magnetic field lines drawn in by arrows can be detected by the magnetic field sensor 72.

[0204] An axial displacement changes the received signal 68 of the sensor device 70 in accordance with the illustration in FIG. 4b. FIG. 4b shows the course of the amplitude 69 of the signal 68 detected by the magnetic field sensor 72 as a function of the axial displacement of the brake components 2, 3 relative to one another. The amplitude 69 of the detected signal 68 changes as a result of an axial displacement of the magnetic field sensor 72 in relation to the magnetic ring unit 71. An axial displacement or pressing down of an operating button 101 can be detected in this way.

[0205] The angle of rotation can also be detected with the same sensor 72, the direction of the magnetic field 8 (arrows shown) being determined to detect the angle of rotation. The intensity determines the axial position. A change in the signal 68 can therefore be used to infer that a button or the snap disk 29 has been actuated. This is advantageous since a single (multidimensional) Hall sensor can be used to determine the angular position and to determine an axial position.

[0206] FIG. 6 shows, purely schematically, two differently designed electrical coils 261, 262, in which case the number of windings can differ. The size/type of diameter and shape and material of the wires 263, 264 can also be different. The size and external shape of the electrical coils 261, 262 can be the same (shown with a solid line) or different, so the second electrical coil 262 can also have a smaller cross section, for example, as shown with a dashed line. As a result, different properties can be set on the magnetic circuits. One magnetic circuit can be designed for a faster reaction speed and/or a higher braking torque, while the other can be designed better in the braking capacity and/or more energy efficient. A wide variety of property combinations can be achieved. The material on the brake gap sections can also be different.

[0207] FIG. 7a shows a schematic cross section of a further brake device 1, the first brake component 2 being accommodated on a holder 4 designed as an axle 12. In this embodiment, too, three brake gap sections 5a, 5b, 5c are provided, with a disk contour 41 being formed on the first and second brake gap section 5a, 5b.

[0208] A reservoir 32 for magnetorheological particles can be present in the interior in order to ensure an adequate supply of the brake gap sections with magnetorheological particles. In particular, carbonyl iron particles are attracted from the environment and concentrated in the magnetic field transition region.

[0209] In FIG. 7a, a cover 14 is attached to the front (left) end and a cover 15 is attached to the rear end.

[0210] The disk body 41 is designed here in one piece with the core 21, but can also be designed as a disk assembly 44 with a plurality of disk plates 46.

[0211] The casing part 13 and thus the brake circuit here has an outer diameter of between 80 mm and 130 mm. In the example here it is 125 mm. The correspondingly large diameter makes it particularly easy to achieve high moments.

[0212] A cable bushing 12a is formed on the hollow axle 12, through which the cables for supplying the two electric coils 261 and 261 are passed. The (separate) core 21 is accommodated on the inner part. On the core 21, the two electric coils 261 and 262 are wound on coil holders 26b. Between the two electrical coils 261 and 262, the ring contour 61 for the third brake gap section 5c is taken or formed. In simple configurations, the ring contour 61 is applied to the core 21 as a separate part and provides a thin gap between the outside of the ring contour 61 and the inner circumference of the casing part 13 are available, as shown above in FIG. 7a. The ring contour 61 can also be formed in one piece with the core, cf. 7a below. The third brake gap section 5c is used to close the two magnetic fields of the two electrical coils 261 and 262.

[0213] The magnetic field of the first electrical coil 261 runs essentially radially through the first brake gap section 5a and the third brake gap section 5c and axially through the core 21 and the casing part 13. The magnetic field of the second electrical coil 262 runs essentially radially through the second brake gap section 5b and the third brake gap section 5c and axially through the core 21 and the casing part 13. The two electrical coils 261, 262 are wound and energized in such a way that the magnetic fields of the two electrical coils 261, 262 in the region of the third brake gap section 5c run in the same direction, as also shown schematically in FIG. 3b.

[0214] Overall, a braking device 1 that can be produced very cost-effectively is made available, with at least one bearing being able to be saved if necessary by bearing via the disk contour 41, which also reduces the overall height. A very low basic friction is achieved. The fact that fewer parts are used, the manufacture becomes simpler and more cost-effective A smaller number of parts also improves the tolerance requirements, since tolerance chains are avoided.

[0215] A braking torque can be set separately with the two electrical coils 261, 262 in each case.

[0216] FIG. 7b shows the braking device 1 of FIG. 7a in a perspective view.

[0217] FIG. 8 shows a schematic cross section of a further braking device 1 which is equipped here with a drive device 307 designed as an electric drive motor 90. The drive motor 90 can rotate the steering unit 301 actively. The drive motor 90 is integrated here in the braking device 1 and e.g., designed as a BLDC motor (brushless direct current motor). Here, the drive motor 90 comprises a core 91 and a winding 92 as well as one or more permanent magnets 93 and a (stationary) carrier element 94. However, designs without permanent magnets (e.g. electrically excited electric motor) are also possible.

[0218] The carrier element 94 is fixed here and is firmly connected to the holder 4, so that a moment can be generated both during braking and during active driving (action=reaction). The aforementioned components of the drive motor 90 are here arranged radially and also axially within the outer circumference defined by the brake gap sections 5a, 5b, 5c. The MRF brake is built, so to speak, radially around the drive motor 90, as a result of which installation space can be saved considerably. This is particularly advantageous in the case of steering devices 1 for autonomously driving vehicles. Because there it is often desired that the steering wheel can be moved forward by a person in the driver's seat by 300 mm, so that the person e.g., can work with a notebook while the vehicle drives autonomously. There is often not enough installation space available in a cockpit for such a large travel distance. With the invention shown here, this space is created.

[0219] FIG. 9 shows a schematic of a circuit for rapid activation of the electric coil 26. The electric coil 26 (magnetic coil) is activated here by an H circuit. This is only indicated in FIG. 9 by switches. A voltage source 35a used in normal operation or in continuous operation with a lower voltage of e.g., 12V provides the voltage for normal operation. For the voltage peaks, a voltage source 35b with a higher voltage of, for example, 18V or 24V is connected via a switch. Then, the lower voltage power source 35a is temporarily disconnected. After this when the maximum current is reached, the higher voltage source 35b is again disconnected from the circuit and the electrical coil 26 and the lower voltage source 35a is reconnected. The switches can be any electrical components that are particularly capable of coupling and decoupling in the millisecond range.

[0220] As a result, the current in the electrical coil 26 reaches the desired value more quickly. In a specific case, the desired current is reached within 10 ms instead of 40 ms. The change between the voltages can take place via an electrical circuit.

[0221] FIG. 10 shows a schematic representation of two generated braking torque curves, the generated braking torque (normalized and therefore dimensionless here) being plotted against the electrically introduced power (normalized and therefore dimensionless here). The curve for a BLDC motor (brushless direct current motor) is shown on the left and the curve for a magnetorheological braking device is shown on the right. It can be seen that the electric motor requires considerably more current than the magnetorheological braking device for the same braking torque a braking torque of 14 requires the electric motor more than 130 normalized power, while the magnetorheological braking device (clearly) requires a power of less than 0.3. The power consumption ratio is greater than 100:1 and is around 500:1 here.

[0222] Magnetorheological clutch devices and brakes have the advantage, among other things, that they only require little power for clutching or for damping movements, are quiet, generate little heat and react very quickly (?ms), etc. The low power requirement is particularly advantageous for battery-operated components such as e.g. electric vehicles, in which the power consumption of all components is automatically reflected in the range of the vehicles. But also for vehicles with combustion engines or electrical devices in general power consumption is an issue.

[0223] The system requires much less electricity than activation via an electric motor alone. In general, it is currently the case for electrically powered motor vehicles that you can travel around 6 km with 1 kWh, while one kWh of battery capacity costs around 230 euros, with one kWh of battery capacity causing around 6 kg more weight. Even if this data will change in the future, energy demand will continue to play an important role. FIG. 11 shows the resulting braking torque curves of a magnetorheological braking device 1 for two different current strength curves over time. The dashed curve in the upper half of the figure represents the conventional course, in which the current intensity is increased directly to the desired current intensity.

[0224] Here, at the point in time 0.1 seconds, the current intensity is increased from 0 amperes to 2 amperes. The resulting course of the braking torque or the coupling intensity is shown in broken lines in the lower half of FIG. 13. The transmittable braking torque increases in the dashed curve from the start time at 0.1 seconds within about 25 milliseconds (time 0.125 seconds) to a read value of about 1.25 (normalized to e.g., an average value or a standard unit) and reaches after about 75 milliseconds (point in time 0.175 seconds) asymptotically (almost) the set limit value of about 1.5.

[0225] If, on the other hand, at the beginning of the clutch or the start of the braking process, the current intensity is increased threefold to, for example, 6 amperes are increased here, as shown by the solid lines, the braking torque increases considerably more and reaches the final value of 1.5 after around 10 milliseconds. Here, the current boost with an increased current is only activated for about 10 ms. After that, as shown by the upper solid curve, the current is reduced to 2 amperes. A significantly faster setting can be achieved by briefly increasing the current (current boost) of the clutch or brake torque. That is This is very advantageous in several respects, since it is possible to stop quickly and experience a more direct haptic feeling. A major advantage of the construction is that no cables, sensors or electronics are required on the outside. A high IP class is therefore possible in all configurations. In principle, everything is behind a mounting panel.

[0226] The electrical coils are preferably completely separated from the space containing the magnetorheological medium, in particular by means of a casting compound.

[0227] In preferred configurations, an axial displacement is possible, in which case, in particular, a liquid volume is displaced in the interior. Sufficient space is preferably provided between a cover and a disk contour so that the medium (or liquid) (carbonyl) therebetween is not compressed. (Otherwise, this could lead to high axial adjustment forces.) This provides an additional MRF reservoir from which particles can flow into the area of the disk contour or the rolling elements. Namely, magnetic particles always flow in the direction of the stronger field since magnetic particles are attracted by the magnetic field gradient.

[0228] The seal preferably runs on the axle. There is rotary movement (more than 100,000 revolutions are possible) and there can be linear movement for the probe. To ensure that the seal does not run in and form a running groove and that the friction is low and the leakage (drag oil) does not become too high over the service life, a corresponding material pairing with a hard running surface is preferred.

[0229] The first brake gap section 5a is preferably equipped with a disk contour. The second braking gap section 5b is equipped in particular with rolling bodies and in particular rollers. Rolling elements and especially rollers with a round inner ring enable a high static moment. A disc contour enables good magnetic field transmission and a high torque at high speeds.

[0230] The combined solution, also called hybrid solution, combines both advantages. In contrast, an axial transition of the magnetic field in the prior art had a smaller transition area and thus resulted in lower braking torques. In addition, an axial magnetic field transition has a smaller distance (radius) and therefore generates less moment. A brake gap section 5a, which is also radial, with a disk contour has a larger diameter and thus generates a larger moment with the same force. In addition, the area is larger because the larger circumference spans a larger area. If the width of the contour disc is greater than ? of the diameter, the braking torque that can be transmitted at the (circumferential) radial braking gap section is already greater than the maximum braking torque that can be transmitted on the axial surface! Finally, due to the lower gap height at the disk contour, the magnetic losses are smaller. All of this results in a higher braking torque, even at higher speeds.

[0231] Volume compensation for the push function can be provided by a membrane at the end of the jacket part. Behind the membrane is a click element like a snap-action disk (Snap Dome). This gives a tactile pressure point. You can also hear the click when the pressure point is reached and the snap-action disk presses the entire button or the shell part back into the starting position (similar to a mouse button on a computer mouse).

[0232] The membrane then seals the MRF space. The volume behind the membrane acts as a volume balance when pressed. In the normal position, the snap-action disc has a bulge. If the button is moved in the axial direction, the stator of the braking device presses against the membrane and the snap-action disc. This will flatten it out.

[0233] Normal glass can be used as the transparent material or PMMA (acrylic glass). The advantage of PMMA is that you can use milky glass, which breaks the light inside and can thus illuminate the entire surface evenly. One or more LEDs can be used for lighting, also with different colors.

[0234] In all configurations, the outer brake component can also be non-rotatable and the inner brake component can be the rotatable component. In this case, the electric coil must be electrically contacted via lines through the outer braking component or e.g., via sliding contacts.

[0235] With the invention presented here, the required working range of the steering device 100 can be divided into several sub-areas. A first portion is provided by the drive device 307 and offers an active drive torque e.g., between 0 and 8 Newton meters. A second sub-area is provided by the first brake gap section 5a and offers a braking torque e.g., between 0 and 5 Newton meters. A third sub-area is provided by the second brake gap section 5b and offers a braking torque e.g., between 0 and 25 Newton meters. Due to the disk contour 41 in the first brake gap section 5a, a particularly high control quality can be achieved for the first partial area. Since this sub-area is particularly important for steering precision, the high control quality here has a particularly beneficial effect on steering behavior.

[0236] The steering device 100 presented here also has the advantage that the necessary active torque (driving torque) can be achieved by a compact and agile electric motor with high control quality and lower power consumption (better efficiency in the partial load range). The required low passive torque (braking torque, for example, up to 8 Newton meters) is achieved here by the first brake gap section 5a with particularly low basic friction and high control quality with low power consumption at the same time. The required higher passive Torque (braking torque, for example, up to 25 Newton meters) is achieved here with the second brake gap section 5b, which also has particularly low basic friction and normal control quality with low power consumption at the same time. This results in triple redundancy.

[0237] At the same time, the steering movement can be influenced noiselessly and smoothly. In addition, in the event of a malfunction of the drive device 307, the braking device 1 can slow down its active torque. In addition, a motor curve (fluctuating torque over the angle of rotation) can be smoothed out or corrected by the braking device 1. In addition, the braking device 1 requires significantly less electricity than an electric motor to generate a comparable braking torque.

[0238] The steering device presented can also be used in combination with the on-board computer, display instrument or a head-up display as a game console or as a driving or flight simulator. When the vehicle is parked (e.g., in the case of electric vehicles, when charging) or the car has a self-driving mode, the user can use the steering device as an input device of a computer game. When changing from gaming mode to real ferry operation, haptic feedback is preferably provided.

[0239] Certain parameters of the steering device can also be set or configured or stored in a customer-specific manner, within system limits, via the on-board computer or other input devices (individualization). The individual settings can be called up using key recognition, smartphone or smart device communication, driver recognition (image recognition; face recognition), gesture control, voice control, data analysis or manual input.

LIST OF REFERENCES

[0240] 1 magnetorheological braking device [0241] 2, 3 brake component [0242] 4 holders [0243] 5 gap [0244] 5a braking gap section for 41 [0245] 5b braking gap section for 11 [0246] 5c braking gap section for 61 [0247] 5d braking gap section [0248] 6 medium [0249] 8 magnetic field, field [0250] 11 rolling elements [0251] 11b gap height of 5b [0252] 11c radial clearance at 5b [0253] 11d diameter of 11 [0254] 11e axial width of 11 [0255] 11f bracket [0256] 12 axis [0257] 12a cable bushing [0258] 13 casing part [0259] 14 cover, lid [0260] 15 cover, lid [0261] 16 pin [0262] 18 bulbs [0263] 19 magnetic particles [0264] 20 axis of rotation, axial direction [0265] 21 core [0266] 22 hub [0267] 23 knob [0268] 26 coil [0269] 26b bobbin holder [0270] 26e axial width [0271] 28 potting compound [0272] 29 snap disk [0273] 29a guide [0274] 29b volume [0275] 31 membranes [0276] 32 reservoirs [0277] 35a power supply 12V [0278] 35b power supply 18V [0279] 38 seal [0280] 39 O ring [0281] 40 star contour [0282] 40c gap height [0283] 41 disc contour [0284] 41a integral annular flange [0285] 41b gap height of 5a [0286] 41e axial width of 5a [0287] 42 ring body, disc body [0288] 42a recording [0289] 43 user interface [0290] 44 disc pack [0291] 45 cables [0292] 46 disk sheet metal [0293] 47 bulged outer contour [0294] 48 filling screw [0295] 49 coating [0296] 50 console [0297] 51 nut [0298] 61 ring contour [0299] 68 signals [0300] 69 amplitude [0301] 70 sensor [0302] 71 magnetic ring assembly [0303] 72 magnetic field sensor [0304] 75 shielding device [0305] 76 shielding bodies [0306] 77 separation unit [0307] 78 decoupling device [0308] 79 sensor board [0309] 79a contact pin [0310] 80 magnetic field concentrator [0311] 90 drive motor [0312] 91 core [0313] 92 winding [0314] 93 permanent magnet [0315] 94 carrier element [0316] 100 steering device [0317] 101 control head [0318] 102 operating roller [0319] 110 closed chamber [0320] 200 device component [0321] 261 electric coil [0322] 262 electric coil [0323] 263 wire [0324] 264 wire [0325] 301 steering unit [0326] 302 steering controller [0327] 303 actuator device [0328] 304 driver assistance system [0329] 305 remanence device [0330] 306 security device [0331] 307 drive device [0332] 311 steering shaft