Abstract: A damper body for a magnetorheological (MR) damper and associated methods of forming the damper body. The damper body is formed of a base material, such as a steel, and is coated with an abrasion-resistant layer comprising chromium. The layer of chromium provides a sliding wear surface for sliding contact with a reciprocating piston. To avoid high-stress abrasive wear over the expected service life of the magnetorheological damper, the layer of chromium has a minimum thickness greater than or equal to a minimum thickness of about 8 &mgr;m. In other embodiments, be fore applying the abrasion-resistant layer of chromium, the damper body is coated with a layer of a hard coating material having a hardness greater than the hardness of the base material. The effective hardness of the damper body is a composite of the respective hardnesses of the base material comprising the damper body and the layer of hard coating material.

Abstract: Oscillating damper comprising: a housing (12) defining a chamber (14) filled with damping fluid, an oscillating plate (22), movable within the chamber (14) and placed so as to divide the chamber (14) into two sections of variable volume (24, 26), and at least one passage (28) created in the oscillating plate (22) to enable the fluid to pass from one section to the other during the motion of the plate (22). The damping fluid is a magneto-rheological or electro-rheological fluid and an electrically-controlled excitation device (30) is placed in correspondence with the passage (28) to control the outflow resistance of fluid passing through the passage (28).

Abstract: A magnetorheological (MR) device (20) including settling stability. The MR fluid device (20) includes a housing (22) including a hollow (30), a moving element (26) contained within the hollow (30), the housing (26) and moving element (26) cooperating to form a working section (36) and a chamber (32) within the hollow (30), a MR fluid (38) contained within the working section (36) and the chamber (32), a coil (40) or the like for generating a magnetic field to act upon the MR fluid (38) contained within the working section (36) to cause a rheology change therein, and a magnet (25) or electromagnet (31) generating a low-level magnetic field to act upon a substantial portion of the MR fluid (38) contained in the chamber (32) to minimize settling of the particles in the MR fluid. Linear and rotary acting embodiments are included.

Abstract: 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 affect 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.

Abstract: A magnetorheological damper includes a cylinder and a magnetorheological piston. The magnetorheological piston is located within and slideably engages the cylinder. The magnetorheological piston includes a magnetically energizable passageway and a magnetically non-energizable passageway spaced apart from the magnetically energizable passageway. The magnetorheological piston also includes a pressure and flow control valve disposed to allow pressure-dependent fluid flow in the magnetically non-energizable passageway when the magnetorheological piston slides towards the first end of the cylinder.

Abstract: 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.

Abstract: A magneto-rheological damping device comprises a core element capable of acting as a magnetic circuit which carries a magnetic flux, and a case element surrounding a portion of the core element. A passage exists between the case element and core element, and an amount of magneto-rheological fluid is positioned between the core element and case element to flow within the passage.

Abstract: An automobile brake device, the device comprising: a brake disc; a brake pedal; a magnetic force generating unit for generating a magnetic force corresponding to amount of manipulation at the brake pedal; and magneto-rheological fluid where intrinsic viscosity of the fluid is changed by the magnetic force to generate shearing force and to apply braking force to the brake disc, such that manipulating power of brake pedal by a driver is immediately transmitted to wheels in response to electric signal, using MR fluid, to enable to embody a rapid response speed while dispensing with hydraulic oil to make brake booster, hydraulic pipe route and cylinder of caliper unnecessary thereto, thereby realizing swift generation of braking power with only simple combination of parts, whereby there is no fear raised about generation of vapor lock phenomenon at hydraulic brake device, and because of no brake pad used, there is no fear either about environmental pollution resulted from fade phenomenon or dust.

Abstract: A controllable medium device for resisting movement (rotary, linear, or sliding) between two relatively moveable members includes a first member and a second member coupled for relative movement having a working space between them, and a controllable medium retaining structure, for example, an absorbent matrix, to hold a controllable medium only in the working space. A field generating coil is mounted to one of the first and second members to generate a field acting on the first and second members and the controllable medium in the working space. The rheology change in the medium produced by the field results in resistance to relative movement of the first and second members. A device according to the invention may be used in apparatus, such as washing machines, exercise equipment, air supported tables, and a range of other apparatuses that would benefit from controlled damping or braking.

Abstract: An improved magnetorheological fluid damper is provided which more closely approximates ideal performance requirements including increased turn-up ratio and stiction free performance near zero velocity for realistic automotive applications. The MR damper includes a magnetic flux leakage reduction device positioned at each end of the magnetic damper piston assembly to create a magnetic flux isolation barrier causing magnetic flux to extend through an annular flow gap thereby minimizing flux leakage into other areas such as a piston rod and associated hollow tube. The magnetic flux leakage reduction devices are formed of a non-magnetic material and completely cover a respective adjacent axial face of a piston core. A laminar flow enhancing feature is also provided for enhancing laminar flow and minimizing turbulence in the annular flow gap thereby advantageously reducing the off-state force and increasing the turn-up ratio.

Abstract: The present invention provides a magneto-rheological controlled damping assembly that eliminates contact between the piston and the damping cylinder and that maintains a constant volume for the magneto-rheological fluid within the damping cylinder, therefore substantially reducing abrasion and wear to the damping apparatus components and increasing the performance and the life of the damping apparatus.

Abstract: An MR fluid damper having a damper body tube containing a volume of MR fluid. A piston assembly is disposed in the damper body tube to form a flow gap between an outer surface of the piston and an inner surface of the damper body tube. An external coil surrounds a portion of the damper body tube. The external coil is capable of generating a magnetic field across at least a portion of the flow gap. In another aspect, the piston assembly includes a bearing in contact with the, inner surface of the damper body tube. The bearing maintains the piston assembly concentric within the damper body tube while permitting a flow of the MR fluid through the flow gap.

Abstract: A magnetically actuated motion control device includes a housing defining a cavity and including a slot therethrough. A movable member is located within the cavity and is movable relative to the housing. A magnetic field generator located on either the housing or the movable member causes the housing to press against the movable member to develop a friction force.

Abstract: A joint member for selectively joining first and second members, said joint member comprising a first coupling member comprising a volume of field responsive material and a second coupling member comprising a field generating member for selectively applying a field across the field responsive material, the joint member also comprising means for selectively moving the field responsive material toward and away from the field generating means.

Abstract: A vibration damping system for absorbing shock loads includes a hydraulic damper containing a piston slidably reciprocating within an oil filled chamber and dividing the chamber into a pair of subchambers. A hydraulic motor is in fluid communication with and located between the subchambers and is controlled by a field responsive fluid, such as an electrorheological (ER) actuated device. The hydraulic motor transforms fluid motion into rotating motion by a pair of meshing gears. The ER device is a flow cell and is connected to a shaft of one or both of the meshing gears. The magnitude of an electric field applied to the ER fluid controls the flow rate of the hydraulic fluid passing through the hydraulic motor by controlling the resistive force to the rotary motion of the gears. A plurality of check valves controls the direction of flow of the hydraulic fluid between the hydraulic motor and the subchambers.

Abstract: A flow control valve assembly for an electro-rheological (ER) fluid has an inlet port, an outlet port and a flow path for ER fluid extending between the inlet and outlet ports. A flow control valve is disposed in the flow path and includes a resilient diaphragm, which is acted upon by pressure in the flow path and which is moveable towards and away from the free end of a hollow boss. A flow restrictor in the form of an annular passage defined by electrodes is disposed in the flow path upstream of the flow control valve. An electric field is applied to the ER fluid as it passes between the electrodes to enable control of the resistance to flow of the ER fluid therethrough, thereby enabling control of the pressure drop across the diaphragm. A bypass passage defining a pressure relief valve is disposed downstream of the flow restrictor and permits flow between the inlet and outlet ports when the flow control valve is closed.

Abstract: An electrical coupling assembly for a damper, the coupling assembly including a base and a rod received through the base. The rod has a threaded connector end and a conductor extending through the rod from the connector end. The coupling assembly further includes a conductive nut threaded onto the connector end of the rod and a plug housing including a ground lead and a power lead, the power lead being electrically coupled to the conductor. The coupling assembly has a conductive member engaging the plug housing and the nut, the conductive member being electrically coupled to the ground lead. The coupling assembly is particularly suited for use in a strut having an outer tube coaxial with the inner tube and connected to the rod and the wheel suspension assembly of the vehicle so as to absorb the side loads applied to the strut.

Abstract: A controllable damper for resisting movement between two relatively moveable members includes a first member and a second member coupled for relative movement having a working space between them, and a controllable medium retaining structure, for example, an absorbent matrix, to hold a controllable medium in the working space. A field generating coil is mounted to one of the first and second members to generate a field acting on the first and second members and the controllable medium in the working space. The rheology change in the medium produced by the field results in resistance to relative movement of the first and second members. According to a preferred embodiment, transmission is included to convert linear motion of a first component to rotary motion of the second member. The transmission allows amplification of the relative speed between the first and second members.

Abstract: An MR fluid damper having an annular flux ring assembly surrounding a piston core piston assembly which is disposed for reciprocal movement in a cylinder. The flux ring assembly has first and second ferromagnetic flux rings forming opposite ends of the flux ring assembly, and a nonmagnetic annular spacer interposed between the ferromagnetic flux rings. The annular spacer has a plurality of first projecting members extending between the piston core and the flux ring assembly. The plurality of projecting members align the piston core concentrically with respect to the flux ring assembly to form an annular, first flow path between the piston core and the annular flux ring. In an alternative embodiment, the annular spacer has a plurality of second projecting members extending between the flux ring assembly and the cylinder. The second projecting members align the flux ring assembly concentrically with respect to the cylinder, thereby forming an annular, second flow path between the flux ring and the cylinder.

Abstract: An improved magnetorheological fluid damper is provided which effectively provides a smooth transition, without a sharp break in the damper force/velocity curve, between very low damping forces near zero damper velocity to higher damping forces at higher piston velocities while maintaining desirable maximum force levels. The damper includes a piston assembly, including a magnet assembly and a flow gap extending through the piston assembly to permit fluid flow between the chambers. The force/velocity optimization feature includes a groove or passage open to the flow gap, positioned in series with a part of the flow gap in a magnetic circuit generated by the magnet assembly and dimnensioned/sized to permit fluid flowing through the passage to experience a magnetorheological effect less than a magnetorheological effect experienced by fluid flowing through the flow gap but not through the groove. Preferably, the passage is formed in an inner annular surface of a flux ring positioned around a piston core.

Abstract: An improved magnetorheological fluid damper is provided which effectively provides a smooth transition, without a sharp break in the damper force/velocity curve, between very low damping forces near zero damper velocity to higher damping forces at higher piston velocities while maintaining desirable maximum force levels. The damper includes a piston assembly, including a magnet assembly and a flow gap extending through the piston assembly to permit fluid flow between the chambers. The force/velocity optimization feature includes a groove or passage open to the flow gap, positioned in series with a part of the flow gap in a magnetic circuit generated by the magnet assembly and dimensioned/sized to permit fluid flowing the passage to experience a magnetorheological effect less than a magnetorheological effect experienced by fluid flowing through the flow gap but not through the groove. Preferably, the passage is formed in an inner annular surface of a flux ring positioned around a piston core.

Abstract: A damper for damping movement of a shaft, the damper including a housing having an inner surface defining a chamber and a rotor rotatably mounted in the chamber. The chamber is filled with magnetorheological fluid such that when the rotor is moved in the chamber the magnetorheological fluid damps the movement of the rotor. The rotor has an outer surface adjacent to and spaced apart from the inner surface. The damper further comprises shaft coupled to the rotor and an outer magnet adjacent the space between the outer surface and the inner surface for restricting the flow of the magnetorheological fluid in the space between the outer surface and the inner surface.

Abstract: Door hinge with a locking device based on a field force, including a cylinder divided by a piston into working spaces that are filled with an operating medium whose viscosity can be changed by means of a field force. The working spaces are connected to one another by at least one flow connection that is subject to the influence of a field force generating element. The door hinge is designed as a pivot bearing, wherein the cylinder takes the form of a bearing eye and the piston takes the form of a rotary piston with at least one blade.

Abstract: A novel and improved magnetorheological fluid damper is provided which effectively secures a flux ring to a piston core in a manner which prevents relative axial and radial movement between the flux ring and the core throughout operation while minimizing the size of the piston assembly yet providing effective damping. Several connector devices are disclosed for both axially and radially securing the flux ring relative to the piston core at one end of the piston assembly in a simple manner without increasing the length of the piston assembly. The connector device may include an outer portion brazed to the flux ring, an inner portion connected to the piston core, bridge portions extending between the outer and inner portions, flow passages formed between the bridge portions and an inlet cavity formed adjacent an annular flow gap to permit unimpeded, enhanced laminar flow through the flow gap by improving the damping effect.

Abstract: A seismic MR damper for providing controllable damping forces between a first structural member and a second structural member within large structures, such as buildings, bridges, etc.

Abstract: A shock absorber includes a housing, a cylinder, a piston rod, a piston and a chamber. The housing has an inner space containing a hydraulic fluid. The cylinder has an upper room filled with a magnetorhelogical fluid and a lower room filled with the hydraulic fluid. The piston rod is movably inserted in the upper room of the cylinder. The piston is movably inserted in the lower room of the cylinder, secured to the piston rod and structured to form a magnetic field generator. The chamber is mechanically connected to the piston rod. The piston rod further includes at least first orifice for providing a flowing path for the magnetorheological fluid and the piston further includes at least a second orifice for providing a flowing path for the hydraulic fluid in the lower room of cylinder.

Abstract: An improved magnetorheological fluid damper is provided which closely approximates ideal performance requirements by providing an increased turn-up ratio and improving the linearity of damping force response. The MR damper includes a plurality of concentric annular flow gaps formed between concentrically mounted flux rings positioned on a piston core. By utilizing multiple flow gaps, the present damper increases the overall magnetorheological damping affect thereby creating a higher damping force and an increased tun-up ratio for a given piston size. Alternatively, the present multiple flow gap design permits a given damping force requirement to be achieved with a piston having a significantly reduced length thereby permitting a longer piston stroke. Also, multiple flow gaps permit greater design optimization for controlling damping force linearity.

Abstract: A magnetic particle damper apparatus is provided for damping motion between two relatively movable members. The damper apparatus comprises first and second conductor members each attachable to one of the relatively movable members. The conductor members are disposed with confronting surfaces having a gap therebetween filled with a quantity of magnetic particles. A magnetic element is attached to one of the conductor members, producing magnetic flux which is substantially confined to a magnetic flux path defined by relatively magnetically permeable regions and relatively magnetically non-permeable regions of the conductor members to flow across the gap and through the magnetic particles. The magnetic field causes the magnetic particles along the flux path to adhere to one another and to the confronting surfaces of the conductor members producing a force opposing relative motion between said movable members and dissipating energy when the conductor members move relative to one another.

Abstract: A controllable damper for resisting movement between two relatively moveable members includes a first member and a second member coupled for relative movement having a working space between them, and a controllable medium retaining structure, for example, an absorbent matrix, to hold a controllable medium only in the working space. A cage preferably supports the matrix. A field generating coil is mounted to one of the first and second members to generate a field acting on the first and second members and the controllable medium in the working space. The rheology change in the medium produced by the field results in resistance to relative movement of the first and second members. A device according to the invention may be used in apparatus, such as washing machines, exercise equipment, air supported tables, and a range of other apparatuses that would benefit from controlled damping or braking. Devices including a two-piece outer housing are described.