1771 results about "Magneto rheological" patented technology

The present invention relates to a variable-torque magnetorheologically actuated prosthetic knee which utilizes a plurality of interspersed and alternating rotors and stators to shear magnetorheological fluid in gaps formed therebetween. Advantageously, by operating in the "shear mode" there is substantially no or negligible fluid pressure buildup or change. Moreover, the multiple MR fluid gaps or flux interfaces desirably allow for the production of a large torque at low speed-eliminating the need for a transmission-and also for a wide dynamic torque range. One embodiment of the invention allows the rotors and/or stators to close the gaps therebetween to create a frictional torque component, thereby forming a "hybrid" braking system which provides a total torque or damping which is a combination of viscous torque and frictional torque.

A magneto-rheological ("MR") damper having a damper body tube containing an MR fluid. A piston assembly is disposed in the damper body tube and forms an annular flow gap between the piston assembly and the damper body tube. The piston assembly has a piston core containing ferrous material and an electromagnetic coil mounted on the piston core for generating a magnetic field. The damper further includes a ferromagnetic member positioned outside of the damper body tube substantially adjacent the piston assembly for providing at least a part of a magnetic flux return path for the magnetic field.

An apparatus and a method for generating haptic feedback and a portable device having the apparatus are provided. The haptic feedback generator changes the property of a magneto-rheological fluid or an electro-rheological fluid using a magnetic field or an electric field and transmits haptic feedback using the property variation. The haptic feedback generator includes a controller 620 outputting a control signal for providing a haptic feedback based on application information selected by a user and a haptic feedback generating unit 610 generating the haptic feedback based on the control signal and providing the haptic feedback in response to an external force F_in of the user.

A tunable vibration isolation device comprising a magneto-rheological elastomer (MRE), and methods of using such a device, are provided. By manipulating a magnetic field within the MRE the device's stiffness is controlled. The vibration isolator can be constructed to provide shock absorption in one, two and three dimensions. Coupling the tunable device to a sensor feedback and a control system provides fast and accurate vibration isolation and energy dissipation for shock events in a variety of applications.

A magneto-rheological (MR) damper provides a higher than minimum level of damping when a power source to the MR damper is not supplying a control current. The present invention damper includes magnets positioned to direct a magnetic flux across a MR fluid path. The fluid path is created when a rod and piston assembly stroke the fluid though a control valve assembly attached to a damper chamber causing a resistance to MR fluid flow. An electric coil cancels an effect of the permanent magnets when the control current is available to allow a control circuit more operating range. The permanent magnets allow for damping when no control current is available.

The present invention relates to the development of water purifying compositions based on magnetic nanoparticles decorated activated carbon nanocomposites which display both magnetic character as well as adsorbent characteristics. The addition of adsorbent to impure water containing dye as pollutant enables the fast adsorption of dye leading to discoloration of water whereas magnetic properties facilitates the rapid isolation of pollutant adsorbed nanocomposites powder from the purified water with the aid of a magnet. The present invention also provides a process for the development of such multifunctional adsorbent using a process which enables decoration of adsorbent with 5-50 weight % of magnetic nanoparticles, the enables the realization of magnetic adsorbent having saturation magnetization in the range 0.09 to 28.3 emu/g, dye removal efficiency of >99%, rapid decolourization of methylene blue (MB)/methyl orange (MO) dye polluted water in less than 1 min, magnetic separation time in the range <0.2 to 60 min and dye sorption capacity in the range of 3.3×10⁻⁴ to 116.3×10⁻⁴ mol of MB and 3.6×10⁻⁴ to 148.6×10⁻⁴ mol of MO dye per 100 gram of nanocomposite powder in a rapid adsorption (<1 min) and magnetic separation process. Besides, these nanocomposites could also be useful for other of applications e.g. as separation of catalytic residues from the products, for removal of oil from water, filler for development of thermally/electrically conducting magneto-rheological fluids or for handling of electromagnetic pollution.

A haptic feedback device is described for providing feedback to a user. The device includes a motor, an output element and a pair of magneto-rheological clutches for selectively coupling the motor with the output element. The pair of clutches are configured to drive the coupled element in opposite directions. The device may be provided in a steering wheel or similar.

A closing system for use with a magneto-rheological (MR) damper. The closing system provides lubrication for a piston rod without a need for periodic replenishment. According to an embodiment of the present invention, a lubrication chamber of the closing system utilizes a carrier fluid portion of MR fluid present in a fluid reservoir of the damper as lubricant for a piston rod guide and the piston rod. A seal retainer comprised of a porous material acts as a selective barrier to the micro-particles in the MR fluid in the fluid reservoir, allowing the MR carrier fluid portion to pass through the porous seal retainer to the lubrication chamber while restraining the micro-particles in the fluid reservoir. The seal retainer thus acts as a filter to segregate the abrasive particles of the MR fluid and allows the MR carrier fluid portion of the MR fluid to continuously replenish the lubrication chamber and lubrication passage to lubricate the piston rod guide and piston rod.

The invention relates to a magneto-rheological torsion damper, which mainly comprises a stator, a rotor, a spiral propulsion rod and a shock absorber cylinder body, wherein the input end of the magneto-rheological torsion damper is connected with loading equipment via a coupler; the stator is wound with multiple stages of electromagnetic coils; a groove or a bulge matched with the rotor is processed on the outer wall of the stator; a certain gap is formed between the outer wall of the stator and an inner sleeve; a bulge or groove matched with the stator is processed on the inner wall of a rotor cylinder; the propulsion rod with a spiral propulsion structure, the rotor and the spiral propulsion rod are mutually connected via a terminal pad; the shock absorber cylinder body consists of an outer sleeve, a sealing bearing, a left cover plate and a right cover plate; a certain gap is formed between the shock absorber cylinder body and the inner sleeve; and the gap between the stator and the shock absorber cylinder body as well as the gap between the shock absorber cylinder body and the rotor is full of magneto-rheological fluid. According to the magneto-rheological torsion damper disclosed by the invention, two working modes of magneto-rheological fluid shearing and flowing are fully utilized, and the magneto-rheological torsion damper has the advantages of compact structure, big adjustable damping force and wide dynamic range and can be widely applied to the occasion of torsional vibration control.

The invention belongs to the technical field of precision optical polish finish, in particular to a polishing method of the inner concave surface of optical elements and a polishing device. A core mould with a tank circuit and inosculating with the shape of the inner concave surface to be processed is fixed below the inner concave surface of a work piece to be processed, and the work piece rotates around the own rotary shaft, keeps a micro clearance from the core mould and applies magnetic fields to processing regions by an external magnetic pole tool head and an internal magnetic pole exciting coil. When magneto-rheological fluids with polishing abrasives flow through the processing region along the tank circuit, a flexible polishing head is formed under the action of magnetic field and absorbed on the inner concave surface and polishing effects are generated. The polishing method and the device can realize the inner concave surface polishing of conformal optical elements with small curvature radiuses or deep cavity structure and other cyclically symmetric high gradient aspheric surfaces, and can remove distribution by utilizing computer-controlled polishing, and besides the polishing method and the device have the polishing surface shape control ability and both the advantages of high precision and high surface quality.

A system for damping vibration in a drill string can include a magnetorheological fluid valve assembly having a supply of a magnetorheological fluid, a first member, and a second member capable of moving in relation to first member in response to vibration of the drill bit. The first and second members define a first and a second chamber for holding the fluid. Fluid can flow between the first and second chambers in response to the movement of the second member in relation to the first member. The valve assembly can also include a coil for inducing a magnetic field that alters the resistance of the magnetorheological fluid to flow between the first and second chambers, thereby increasing the damping provided by the valve. A remanent magnetic field is induced in one or more components of the magnetorheological fluid valve during operation that can be used to provide the magnetic field for operating the valve so as to eliminate the need to energize the coils during operation except temporarily when changing the amount of damping required, thereby eliminating the need for a turbine alternator power the magnetorheological fluid valve. A demagnetization cycle can be used to reduce the remanent magnetic field when necessary.

In a variable damper using magneto-rheological fluid that comprises a cylinder (12) filled with the fluid, a piston (16) slidably received in the cylinder and including an inner yoke (32; 62; 126), an outer yoke (31; 64, 65; 140) and a coil (34; 130), a piston rod (13) having an inner end attached to the piston and an outer end extending out of the cylinder and a magnetic valve formed in a gap between the inner and outer yokes, at least one of the outer yoke and inner yoke consisting of at least two parts that are joined to each other in an axial direction. The two piece arrangement of the inner yoke or outer yoke allows the end plates to be omitted because the gap spacer can be installed without requiring end plates, and this contributes to a compact design and a favorable damping property. Also, the manufacturing and servicing of the damper can be simplified. When end plates (134) are used, the freedom in the positioning of the coil is increased.

The invention relates to a multi-disc type magneto-rheological stepless speed changer which mainly comprises a magnetic isolation hub, an input shaft, an output shaft, a driving friction plate, a driven friction plate, magnetic exciting coils and magnetic isolation rings; wherein the driving friction plate and the driven friction plate are respectively fixed on an outer magnetic isolation circular ring and the magnetic isolation hub through the magnetic isolation rings; a right magnetic conducting lateral plate is connected with the input shaft through a big magnetic isolation circular ring and a left magnetic conducting lateral plate; the output shaft is connected with the driven friction plate and the magnetic isolation hub; magneto-rheological fluid is sealed between the driving friction plate and the driven friction plate through a seal ring; the magnetic exciting coils are fixed on two bearing seats through a magnetic conducting shell, the left magnetic isolation lateral plate and the right magnetic isolation lateral plate in a motionless way, and the driving friction plate and the driving friction plate are in interleaved matching and isolated through the magnetic isolation rings. The shear yield stress of the magneto-rheological fluid can be changed by adjusting the electric current of the magnetic exciting coils, therefore, the speed difference between a driving shaft and a driven shaft is changed, and the stepless speed change is further realized. The invention has the advantages of simple structure, no electric sparks, high transmission torque and large transmission power.

The tactile transmission device includes a plurality of cells arranged at regular intervals, each having a storage space therein. A contact member is installed in each of the cells, an upper portion of the contact member protruding out of the cell. An elastic member is installed in each of the cells, and biases the contact member upwards. A sensor is installed in each of the cells, and measures displacement of the contact member. A magneto-rheological fluid is contained in each of the cells. A coil is installed in each of the cells and generates a magnetic field in the cell. A control means compares a shape information value of the image with a displacement value of the contact member output from the sensor, thus controlling a quantity of current applied to the coil. According to the present invention, the shape information of an image displayed on a screen is corrected to be suitable for a user's characteristics, thus more precisely transmitting the shape information on the screen to the user. Further, a transmission medium for transmitting a tactile sensation to a user has a simple construction, so that miniaturization of the tactile transmission device is very easily realized.

The invention discloses a combination machining method for removing high-frequency errors in optical elements. The combination machining method includes measuring surface shape errors of an optical element to be machined by an interferometer, carrying out PSD (power spectral density) analysis, and determining distribution characteristics of the medium and high-frequency errors on the basis of a DSD curve; acquiring an optimized removal function model according to predetermined machining time and machining precision, and acquiring an amplitude spectral line of a removal function; acquiring cut-off frequency of the removal function according to the amplitude spectral line; machining by a magneto-rheological finishing process if correctable medium and high-frequency errors with the frequency lower than the cut-off frequency exist according to the frequency distribution of the medium and high-frequency errors; and machining by a computer controlled optical surfacing process if uncorrectable medium and high-frequency errors with the frequency higher than the cut-off frequency exist according to the frequency distribution of the medium and high-frequency errors. By the combination machining method, technical advantages of MRF (magneto-rheological finishing) and technical advantages of CCOS (computer controlled optical surfacing) can be sufficiently combined, efficient uniform convergence of all-band errors of the optical element can be realized, and performance of the optical element is effectively improved.

A method and a device for polishing a magneto-rheological inclined shaft relate to the technical field of precise finishing machining. A polishing tool head and the axial direction of a workpiece have an angle so that the normal of the working arc of the polishing tool head is coincident with the polishing surface normal of the workpiece; the shell of the polishing tool head rotates; furthermore, the rear end of the shaft in the shell passes through the hollow shaft of an adjustable speed motor and is fixedly connected with a machine body; the fixed shaft is provided with an excitation device; one part of the small front area of the shell of the polishing tool head is provided with a magnetic field and the other part thereof has no magnetic field or has weak magnetic field, thus facilitating updating the magneto-rheological liquid; the contact point of the workpiece and the magneto-rheological point is always the normal direction of the polishing area of the workpiece; the shell of the polishing tool head rotates and the magneto-rheological body generates a high shearing force at the clearance between the polishing tool head and the workpiece, thus removing trace of the material. By adopting the inclined shaft polishing, the interference is prevented from being generated; by planning path and controlling relevant parameters, the specific ultra-precise polishing process can be carried out to the surfaces of minitype non-spherical optical parts, dies and workpieces of general dimensions.

Systems and methods relating to a clutch system for use in controllably transmitting torque from an input shaft to an output shaft. The clutch system has a torque transmission fluid that has a viscosity that changes based on the strength of an electromagnetic field passing through the fluid. A number of sensors are placed at different radial locations on the torque transmission disks to detect the strength of the electromagnetic field. Based on the strength of the electromagnetic field, the amount of torque being transmitted from the input shaft to the output shaft can be adjusted. Also disclosed is a distributed actuation architecture that uses this clutch system. The distributed actuation architecture allows for the use of a single drive motor in conjunction with multiple instances of the clutch system to actuate a mechanical linkage, such as a robotic arm.

A fixture is isolated from the transmission of vibration emanating from a vibration source by a damper containing magneto-rheological (“MR”) fluid and a plunger mechanically coupling the damper and the fixture. The isolation apparatus is mechanically coupled to the vibration source. The viscosity of the MR fluid contained in the damper is controlled by a magnetic field produced by the vibration of an isolation system responsive to the vibration of the vibration source. The resonant frequency of the isolation system is adjusted to approximate that of the fixture.

An assembly is provided for fixing the position of an adjustable component (22) of a vehicle, comprising in combination a fixed reference frame (20) within the vehicle such as a dash or a firewall, an adjustable component (22) also disposed in the vehicle such as an adjustable steering column (10), pedals, or a seat. Interconnecting the fixed reference frame (20) and the adjustable component (22) is a fluid locking mechanism (50) which permits selective positioning of the adjustable component relative to the fixed reference frame (20) and holds the adjustable component (22) in position. The fluid locking mechanism (50) is preferably a non-Newtonian flow fluid locking mechanism which uses a magneto-rheological fluid (97) to fix the position of the adjustable component (22) in place once the desired position is selected. To provide additional safety for the vehicle occupants, the fluid locking mechanism may be controlled by an electrical microprocessor (556) or circuit which adjusts the locking strength of the fluid locking mechanism (50) based upon user inputs and dynamic events.

The invention relates to a water-based magnetorheological polishing solution for optical manufacture, which is formed by the following volume components, water-based remixed carrier liquid 25%-75% and additive component 25%-75%, wherein the additive component is dispensed by the following volume percentage, carbonyl iron powder 80%-90%, nanometer iron powder 4%-10% and polishing powder 4%-10%, the water-based remixed carrier liquid which is measured according to volume percentage comprises deionized water 85%-90%, dispersing agent 3%-5%, wetting agent 2%-5% and thixotropic agent 3%-5%, the method for preparing comprises the following steps: mixing deionized water and thixotropic agent, stirring in indoor temperature for 1-2 hours, and adding dispersing agent, stirring in indoor temperature for 0.5-1 hour, and then adding wetting agent, stirring in indoor temperature for 0.5-1 hour, getting water-based remixed carrier liquid, mixing additive component and water-based remixed carrier liquid, adding into a ball-milling tank, adding into a steel ball according to mass ratio which is 1:10, grinding for 3-5 hours in the speed which is 20-30r/m, separating out a steel ball, and getting products. The polishing solution of the invention has the advantages of excellent stability, high rheological property, excellent oxidation resistance property and simple and environmental-friendly preparation technology.

The invention relates to an engine vibration isolation device of a magneto-rheological fluid damper in extrusion mode and a magneto-rheological elastomer in shearing mode for supporting static loads. The vibration isolation device comprises two pars of a damping adjusting unit and a rigidity adjusting unit; the damping adjusting unit is connected with the rigidity adjusting unit through a rigid connecting rod; the vibration of an engine causes the connecting rod to move upwards and downwards, so that the magneto-rheological fluid in the damping adjusting unit flows in radial direction and shearing occurs to the magneto-rheological elastomer in the rigid adjusting unit; a magnetic field generated by two exciting coils can be respectively adjust damping parameters and rigidity parameters of a vibration isolator. The magneto-rheological vibration isolator can meet the independent adjustment of the damping parameters and the elastic parameters of the vibration isolator under different vibrational excitation conditions, and achieve the coupling control of the transmission of engine vibration energy, and has great realistic significance in improving the technical level and market competence of special vehicles.

The invention relates to a flexible mechanical arm vibration reduction device and method based on a magneto-rheological technology, which belongs to the technical field of flexible mechanical arm vibration control. The vibration reduction device comprises a rigid-flexible coupled mechanical arm, a magneto-rheological elastomer vibration reduction device and a feedback control loop, wherein the rigid-flexible coupled mechanical arm comprises a rigid mechanical arm, a motor mounting plate, a servo motor, a harmonic reducer, a flexible mechanical arm mounting base and a flexible mechanical arm; the magneto-rheological elastomer vibration reduction device comprises an iron core, a guide rod, a fixed seat, a magneto-rheological elastomer, a permanent magnet and an electromagnetic coil; and the feedback control loop comprises two acceleration sensors, a charge-amplifier, a data acquisition system, a PC (Personal Computer) upper computer and a programmable power supply. The PC upper computer is used for regulating the supply voltage of two ends of the electromagnetic coil through the analyzing and processing the feedback signals of the two acceleration sensors so as to change the rigidness of the magneto-rheological elastomer, thereby meeting the resonance requirement in a system. The flexible mechanical arm vibration reduction device has the characteristics of obvious vibration reduction effect and less energy consumption and is suitable for large amplitude vibration reduction.

In a magneto-rheological variable damper (6), the piston (16) comprises an inner yoke (32), an outer yoke (31) concentrically surrounding the inner yoke and held in position by pair of end plates (33, 34) made of non-magnetic material and disposed on either axial end surfaces of the piston. The piston may be circumferentially surrounded by a piston cover (30) that may be made of non-magnetic material and serves a slide member that engages the inner circumferential surface of a cylinder (12). Alternatively, the end plates may serve as the slide member. In either case, the durability of the damper can be improved by using a wear resistant material for the slide member. In particular, the outer yoke may be made of material such as Permendur which has a high saturation magnetic flux density but a poor mechanical property. Thereby, the range of the damping force can be expanded. The slide member may be made of non-magnetic material having a favorable wear resistance such as austenite stainless steel and aluminum alloy. It is also possible to apply a plating or other surface processing to the sliding surface of the slide member to improve the wear resistance thereof.