Abstract: The invention provides a magnetorheological piston and damper assembly. The piston includes a piston body including at least one bypass port and an annular gap formed therein. The bypass port is in fluid communication with the annular gap. The bypass port includes a longitudinal portion extending substantially parallel to a piston longitudinal axis, and a bend portion extending substantially away from the longitudinal axis. The annular gap is spaced apart from the longitudinal portion and extends substantially parallel to the piston longitudinal axis. During operation, fluid flows through the bypass port and annular gap. The damper assembly includes a rod and a housing including the fluid carried therein. The piston is slidably carried in the housing and operably attached to the rod.

Abstract: A cushioning body is made by molding a mixture of shock absorbing gel (heat resistant elastic member) made of polyurethane resin and ferrite particles (electromagnetic wave blocking members) into a box. Since the shock absorbing gel is in a form of gel, it does not have fluidity but has stability in shape, and further has not only shock absorbing ability but also heat resistance and heat radiation ability deriving from thermal conductivity. The ferrite particles are locally distributed on a main board side of a bottom portion of the cushioning body and have an electromagnetic wave blocking ability by absorbing or reflecting the electromagnetic wave to prevent transmittance of the electromagnetic wave.

Abstract: The invention provides a magnetorheological damper assembly and piston. The assembly includes a housing with a fluid carried therein, a piston slidably carried in the housing, a rod and a valve both operably attached to the piston. The piston includes at least one passageway formed therein. The valve includes at least one bypass opening formed therein and at least one variable opening formed between a piston surface and the valve. The valve provides asymmetric fluid flow through the passageway. During operation, the variable opening selectively restricts fluid flow and the bypass opening maintains fluid flow through the passageway.

Abstract: A magnetorheological (MR) vibration damper for damping axial and rotational vibrations of an automotive steering system may include a housing encasing MR fluid therein and a gear-like rotor and orifice plate disposed within the housing. The rotor and orifice plate, which may be affixed to the steering wheel shaft, includes a plurality of gear-like teeth on its surface and a plurality of holes for producing shear and normal forces, respectively, on the MR fluid. Electric coils may be disposed within the housing for generating an electric field for activating the MR fluid. The MR vibration damper may be activated or deactivated by a controller by comparing a signal value from a steering wheel vibration sensor to a predetermined threshold value. The controller may be programmable by a user to increase or decrease the predetermined threshold value, so as to enable customization of driving feel.

Abstract: A system and method of controlling engine vibration mounted within a vehicle including at least one hydraulic mount, each mount including a fluid chamber. A pair of accelerometers sense relative acceleration across the mount between the engine and the frame and generate a relative acceleration signal. A control unit is electrically connected to the accelerometers. The control unit is adapted to generate an electronic control signal in response to the relative acceleration signal. The control device is responsive to the electric control signal for controlling the damping force of the hydraulic mount. A control algorithm calibrates the control unit such that maximum vibration damping occurs at and around the engine resonance bounce frequency.

Abstract: A shock and vibration isolation system for mounting equipment to a base wall uses a semi-active damper in parallel with a spring arrangement to provide optimum isolation with respect to both shock and vibration. The system comprises a load plate configured for attachment of the equipment thereto and a base plate configured for attachment to the base wall. The base plate is substantially parallel to the load plate with a spring arrangement disposed intermediate the load plate and the base plate. The spring arrangement engages the load plate and the base plate to bias the load plate and the base plate in a separated relationship. The system also comprises a damping arrangement disposed intermediate the load plate and the base plate. The damping arrangement is adapted for providing a selectively variable reaction force to the load plate and the base plate responsive to a relative displacement of the load plate with respect to the base plate.

Abstract: A passive force element on the basis of electrorheological liquids includes a piston with a piston rod guided in a cylindrical housing, and a force introduction element connected with the piston rod. The piston forms, in the cylindrical housing, two variable-volume working chambers, which are filled with electrorheological liquids, and which are connected by a fluid connection including a valve arrangement with an electrorheological liquid valve for controlling the throughflow characteristic. A regulated damping characteristic can be adjustedly set and force peaks are avoided, because the force introduction is achieved via the force introduction element, and the piston is coupled onto the force introduction element via an elastic element.

Abstract: A piston-cylinder assembly includes a cylinder, in which a piston rod with a piston is guided axially by a piston rod guide. A distance detection system is used to determine the position of the piston in the cylinder. The distance detection system includes a sensor and a transmitter. The sensor is mounted on the piston or on the bottom of the cylinder. Upon axial displacement of the piston, the transmitter travels a distance different from that traveled by the piston, the difference between the two distances being used to determine the position of the piston.

Abstract: The invention relates to a knee-joint prosthesis with a hydraulic damping cylinder (1) for regulating the swing phase control and stance phase stabilization, and with an electronic control for a force field acting on the hydraulic fluid of the damping cylinder (1), the viscosity of the hydraulic fluid being able to be changed by the force field. The object of the present invention is to make available a knee-joint prosthesis whose electronic control has a high degree of safety and a minimal power consumption. According to the invention, the object is achieved by the fact that an actuating member (6, 7, 9, 12) is provided which generates a permanent force field and acts on the hydraulic fluid with an existing force field which is weakened or strengthened by the electronically controlled force field.

Abstract: A system that includes a magnetically actuated motion control device comprising 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 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. The flux caused by the magnetic field flows through the housing, the movable member and at least one pole located along the movable member. The at least one pole comprises a first portion having a first axial dimension and a second portion having a second axial dimension where the first axial dimension is greater than the second axial dimension and as a result the magnetic flux through the second portion of the at least one pole has a greater magnitude than the magnetic flux through the first portion of the pole.

Abstract: A method and apparatus for controlling the tension in a bobbin assembly having a supply bobbin with yarn thereon. As the yarn is fed to a drive bobbin, a magnetic field is variably applied to magnetorheological fluid to apply resistance to the supply bobbin as it rotates thereby controlling the tension on the yarn.

Abstract: A haptic input device comprises a hexapod or pentapod parallel linkage mechanism with force feedback effected by proportional control of magneto-restrictive fluid brakes constraining the measurement of the struts of the mechanism, through their base nodes. In the pentapod version of the haptic data input device, a haptic stylus is employed which includes an annular compliant feature that can be squeezed and whose squeeze pressure can be monitored.

Abstract: A single fluid valve device operable for setting an overall viscous damping level, magnetic damping strength, and low speed damping profile. A stationary, controllable magnetorheological fluid valve device comprising a first annular body having gap setting features and controllable passageways formed within the fluid valve device, and a second body disposed adjacent to the first annular body, wherein the second body comprises a magnetic field generating means contained therein. A twin-tube damping device comprising an outer member containing an outer volume of magnetorheological fluid, an inner member containing an inner volume of magnetorheological fluid, a stationary, controllable fluid valve device disposed within the outer member, a piston rod mounted for movement with respect to the inner and outer members, a piston assembly attached to the piston rod and a pressurized volumetric compliance means.

Abstract: A reduced drag wet disc brake assembly is disclosed in which the viscosity of the fluid in the assembly is capable of changing. At higher traveling speeds, the viscosity of the fluid is low. However, when the viscosity of the fluid increases the speed of the vehicle decreases. The wet disc brake assembly comprises a brake cavity, a rotating plate disposed within the cavity that is rotatingly connected to the hub, two non-rotating plates disposed within the cavity on either side of the rotating plate, a current source connected to the rotating and non-rotating plates, and an electrorheological fluid filling the brake cavity. The viscosity of the electrorheological fluid changes depending on the electric current experienced by the fluid. In an alternative embodiment, the brake assembly also includes a coiled conductive wire connected to a current source to produce a magnetic field and the cavity is filled with magnetic Theological fluid instead of electrorheological fluid.

Abstract: A magnetorheological fluid actuated damper. At least a first and a second cylinder with the first cylinder positioned axially within the second cylinder are provided. A gap is formed between the cylinders. The second cylinder is mounted to a stationary mount of the vehicle chassis and a control arm is mounted at an end of the first cylinder. The first cylinder is mounted on bearings to allow it to rotate relative to the chassis. The gap between the cylinders contains a magnetorheological fluid having an adjustable viscosity in reaction to the application of a magnetic field. A magnetic field is generated over the fluid in the gap.

Abstract: The subject inventive steering damper assembly includes a rotor sleeve having open first and second ends and a drive plate disposed in the open second end. A core is co-axially disposed in the rotor sleeve closing the open first end of the rotor sleeve and defining a magnetic fluid chamber with the sleeve. A Magneto-Rheological fluid is disposed in the magnetic fluid chamber. The drive plate is flexible to provide manufacturing and operational tolerance, and is securely attached to the open second end of the rotor sleeve. Flexibility is derived from at least one aperture disposed in the drive plate. The aperture may be formed in a variety of shapes including elongated, round and oval shaped apertures.

Abstract: A damper in which magnetic particles are difficult to sediment irrespective of the kind of a magnetic fluid is provided. A damper is constituted of a vessel in which the magnetic fluid is accommodated and a slider (piston). As the piston, one that is made of a laminated body of a paramagnetic substance and a non-magnetic substance is used. When thus constituted, the magnetic particles stick to the piston. Accordingly, whatever magnetic fluid is used, the particles do not sediment. The laminated body that is used as the piston has the non-magnetic substance at both ends thereof. When the laminated body is thus constituted, the magnetic particles sticks uniformly. When the laminated body has the magnetic substance at both ends, magnetic particles stick to both ends needle-like.

Abstract: The present invention relates to an electromagnetic brake. In an electromagnetic brake (11) comprising an electromagnetic brake body (13) having yoke members (15a and 15b) with a coil winding (14) and a brake movable member (16) formed of a magnetic material, which is disposed via an air gap (18) in a magnetic path formed by the electromagnetic brake body (13) and is fixed to a motor rotating shaft (2b), a magnetic fluid (20)is filled in the air gap (18), and a sealing member (19) for rotatably sealing the motor rotating shaft (2b) is disposed between the electromagnetic brake body (13) and the motor rotating shaft (2b) to prevent the magnetic fluid (20) from leaking, whereby the electromagnetic brake (11)is applied when the coil winding (14) is excited.

Abstract: A system that includes a magnetically actuated motion control device comprising 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 damper for dampening vibrations of a rotatable steering shaft of a motor vehicle comprises a rotor and means for rotating the rotor at a rate proportional to and greater than rotation of the steering shaft. Magnetorheological fluid is disposed at least partially around the rotor, and has a viscosity variable to vary a load on the rotor.

Abstract: An adjustable vehicle suspension strut configured to be arranged between a wheel assembly and a body of a vehicle, the adjustable strut including a tube. A piston is slidably carried in the tube on a piston rod. A coil is carried on the piston adjacent a first flow passageway in the piston to produce a magnetic field thereacross and a control valve is carried on the piston controlling fluid flow through a second flow passageway in the piston. The control valve is positioned at the distal end of the rod upstream of the first flow passageway.

Abstract: A magnetorheological piston includes a body having a substantially magnetically energizable passageway and a substantially magnetically non-energizable passageway. The substantially magnetically non-energizable passageway has a valveless passageway throat and has a flow cross-sectional area which has a minimum at the passageway throat and which is larger away from the passageway throat. A magnetorheological damper includes a cylinder and the above-described magnetorheological piston, wherein the piston is positioned in, and slideably engages, the cylinder.

Abstract: The damper assembly, in accordance with the teachings of the present invention, can be tuned to different frequency to dampen the vibrations of the driveline assembly. The damper assembly comprises an outer housing, an inner housing and a recess defined between the inner housing and the outer housing. A magnetorheological elastomer is housed in the recess. In order to change the elastic modulus of the magnetorheological elastomer at least one magnetic means is provided in the contact with the inner housing. The magnetic means are capable of being rotated either towards the inner house or away from the inner house such that the elastic modulus of the magnetorheological elastomer is either increased or decreased.

Abstract: A motor system includes an electric motor, a shaft extending through the motor and through a magnetorheological fluid stopper, which comprises a rotor and a stator in operable communication with the rotor. A magnetorheological fluid is disposed at the rotor and the stator.

Abstract: A magnetorheological piston includes a body having a substantially magnetically energizable passageway and a substantially magnetically non-energizable passageway. The substantially magnetically non-energizable passageway has a valveless passageway throat and has a flow cross-sectional area which has a minimum at the passageway throat and which is larger away from the passageway throat. A magnetorheological damper includes a cylinder and the above-described magnetorheological piston, wherein the piston is positioned in, and slideably engages, the cylinder.

Abstract: A passive force element on the basis of electrorheological liquids, in which there is arranged a piston with piston rod, which is guided in a cylindrical housing, whereby the piston rod is connected with a force introduction element, and whereby the piston forms, in the cylindrical housing, two variable-volume working chambers, which are filled with electrorheological liquids, and which are connected by a fluid connection, and whereby the fluid connection comprises a valve arrangement for controlling the throughflow characteristic, which comprises an electrorheological liquid valve, is to be further embodied in such a manner, that a regulated damping characteristic can be adjustedly set and force peaks are avoided. This is achieved in that the force introduction is achieved via a force introduction element and the piston (11, 12, 13, 14) is coupled onto the force introduction element via an elastic element.

Abstract: A magnetorheological piston includes a body having a substantially magnetically energizable passageway and a substantially magnetically non-energizable passageway. The substantially magnetically non-energizable passageway has a valveless passageway throat and has a flow cross-sectional area which has a minimum at the passageway throat and which is larger away from the passageway throat. A magnetorheological damper includes a cylinder and the above-described magnetorheological piston, wherein the piston is positioned in, and slideably engages, the cylinder.

Abstract: The invention provides a vehicle damper assembly including a housing including a fluid carried therein, a piston slidably carried in the housing, and a rod operably attached to the piston. The piston includes a curved portion positioned adjacent a housing inner surface. The invention further provides a vehicle damper assembly including housing means for carrying a fluid, piston means from reducing binding contact with the housing means, and rod means for moving the piston means. The invention further provides a method of reducing binding contact in a vehicle damper assembly. A longitudinal radius is determined for a piston based on a housing inner surface. The piston is formed with a curved portion based on the longitudinal radius. The curved portion is positioned adjacent the housing inner surface.

Abstract: A damper for dampening vibrations of a rotatable steering shaft of a motor vehicle comprises a rotor and means for rotating the rotor at a rate proportional to and greater than rotation of the steering shaft. Magnetorheological fluid is disposed at least partially around the rotor, and has a viscosity variable to vary a load on the rotor.

Abstract: A variable road feedback device (20) for a steer-by-wire system (50) comprises a housing (31) that contains a magnetorheological fluid (32), a magnetic field generator (34) for generating a variable magnetic field within the housing (31) in order to vary the viscous resistance of the magnetorheological fluid (32) therein, and a rotor (24) rotatably mounted within the housing (31) that rotates through the magnetorheological fluid (32) and is responsive to the variable viscous resistance thereof.

Abstract: A temperature compensation method for controlling a damping force of a magnetorheological (MR) damper is disclosed. First, a base operating current as a function of a desired force level of a damping force of the MR damper is determined, and a temperature compensation as a function of an operating temperature of the MR damper is determined. Finally, the temperature compensation is applied to the base operating current to generate a compensated operating current as a function of the desired force level of the damping force and the operating temperature of the MR damper. To refine the compensated operating current, the temperature compensation can be determined as both a function of the operating temperature of the MR damper and a relative velocity of the MR damper.

Abstract: A linear vibration damping system includes a piston slideably disposed within a cylinder, a magneto-rheological fluid disposed within the cylinder, and a magnet disposed in magnetic communication with the magneto-rheological fluid. A rotary vibration damping system includes a cylinder having a steering shaft extending therethrough, a magneto-rheological fluid disposed between an inner surface of the cylinder and an outer surface of the steering shaft, and a magnet disposed in magnetic communication with the magneto-rheological fluid. In either system, the magnet is controllable to provide variable control of the magneto-rheological fluid. A method of damping vibrations in a motor vehicle includes disposing a magneto-rheological fluid at a source of vibration in the motor vehicle, controlling the magneto-rheological fluid to effectuate a structural change in the magneto-rheological fluid, and subjecting the magneto-rheological fluid to a vibration from the source of the vibration.

Abstract: 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.

Abstract: A method for controlling the damping force of a damper containing a movable object in a magneto-rheological fluid, in which a positive magnetic field is applied to the fluid to achieve an increase in viscosity (and an increase in damping force) and the polarity of the magnetic field is reversed by negative electrical energy to remove residual magnetism before reestablishing the magnetic field at a lower level to achieve a predictable decrease in viscosity (and a decrease in damping force).

Abstract: An adjustable vehicle suspension strut configured to be arranged between a wheel assembly and a body of a vehicle, the adjustable strut including a tube. A piston is slidably carried in the tube on a piston rod. A coil is carried on the piston adjacent a first flow passageway in the piston to produce a magnetic field thereacross and a control valve is carried on the piston controlling fluid flow through a second flow passageway in the piston. The control valve is positioned at the distal end of the rod upstream of the first flow passageway.

Abstract: A radial magnetorheological damper is provided which includes a plurality of alternating inner and outer sleeves, a magnetorheological fluid interspersed between them, a return path to return magnetic flux, and a wire coil to produce magnetic flux in the circuit.

Abstract: A damper includes a housing, a piston, and a magneto-rheological (MR) fluid. The piston is movably disposed within the housing such that the piston divides an interior of the housing into first and second cavities and a passage defined in the piston couples the first and second cavities. The passage includes at least a disk shape space within the piston defined between by two substantially parallel surfaces. The MR fluid damps motion of the piston by a flow of MR fluid through the passage, and a magnet produces a magnetic field within at least the disk shape space of the passage.

Abstract: An adjustable vehicle suspension damper configured to be arranged between a wheel assembly and a body of a vehicle, the adjustable damper including a tube. A piston is slidably carried in the tube. A coil is carried on the piston adjacent a first flow passageway in the piston to produce a magnetic field thereacross and a control valve is carried on the piston controlling fluid flow through a second flow passageway in the piston.

Abstract: A piston assembly for use with an MR fluid damper. The piston assembly has a piston core and a flux ring positioned in a desired alignment with the piston core so that the flux ring forms an annular flow gap the piston core. The flux ring is secured to the piston core in the desired alignment by a plurality of projections extending across the flow gap between an inner surface of the flux ring and an outer surface of the piston core. The projections are molded through flux ring holes intersecting the inner and outer surfaces of the flux ring. A method for making the piston assembly is also described and claimed.

Abstract: An improved magneto-rheological (“MR”) fluid damper includes a damper cylinder containing a volume of MR fluid. The cylinder includes an inner surface. A piston assembly is disposed in the cylinder and has an outer surface in slidable contact with the cylinder inner surface. The piston assembly includes a flow gap formed thereabout and an external coil surrounding a portion of the cylinder, the external coil capable of generating a magnetic field across at least a portion of the flow gap.

Abstract: The invention relates to an electrically variable spring/mass vibrating force coupler with variable damping, electrically adjustable spring characteristic curves and electrically adjustable, variable natural frequencies using electro-rheological or magneto-rheological fluids in its coupling elements to couple masses and springs

Abstract: A piston rod for use in a magnetorheological dampening device having a surface finish that renders the device resistant to wear at the elastomeric seal/piston rod interface. The piston rod has a surface finish of Ra<0.065 &mgr;m and &Dgr;a≦1.4°, as measured using a Gaussian filter with a 0.08 mm cut-off length. There is further provided a method of achieving the surface finish, including rotating the piston rod while moving an abrasive tape against the outer surface of the rod.

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 at least one groove open to the flow gap, formed in a non-magnetic portion of the piston and 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.

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, before 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: A magnetorheological damper includes an inner tube, a magnetorheological piston, and an outer tube. The magnetorheological piston is located within and slideably engages the inner tube. The outer tube surrounds the inner tube. The outer tube is in fluid communication with the inner tube.

Abstract: A vibration damper assembly to dampen the vibration generated in a motor vehicle and transmitted through, for example, a steering assembly. The vibration damper assembly includes a rotor disposed within a housing. The rotor is operatively connected to a velocity generating member such as a pinion that is integrated with the steering assembly. A conductive sleeve is disposed between the housing and the rotor. A coil engages the sleeve and is capable of generating a magnetic field that is transmitted through the sleeve. A plate separates the rotor from the sleeve thereby defining a viscous fluid chamber and a Magneto-Rheological (MR) fluid chamber between the rotor and the sleeve. The viscous fluid chamber includes a Newtonian fluid and the MR fluid chamber includes a MR fluid having sheer properties reactive to the magnetic field.

Abstract: A vehicle suspension damper assembly is provided which includes a cup member with a threaded opening formed therein. A piston rod includes a threaded portion, which is engaged in the threaded opening. An electrical connector including a terminal portion is received in an opening formed in the piston rod. The threaded engagement between the piston rod and the cup member is a predetermined length that reduces deflection of the cup member to reduce transfer of load to the terminal portion of the electrical connector.

Abstract: A piston assembly for use with an MR fluid damper. The piston assembly has a piston core and a flux ring positioned in a desired alignment with the piston core so that the flux ring forms an annular flow gap the piston core. The flux ring is secured to the piston core in the desired alignment by a plurality of projections extending across the flow gap between an inner surface of the flux ring and an outer surface of the piston core. The projections are molded through flux ring holes intersecting the inner and outer surfaces of the flux ring. A method for making the piston assembly is also described and claimed.

Abstract: A magneto-rheological (“MR”) damper having a gas cup that slidably moves within a damper body tube and isolates an MR fluid from a gas in one end of the damper body tube. The gas cup has a dynamic seal that comprises an MR fluid compatible O-ring located in a narrow O-ring groove disposed in an outer surface of the gas cup. The narrow O-ring groove is sized to reduce entrapment of abrasive magnetic particles in the MR fluid between the O-ring and an inner surface of the damper body tube. The O-ring groove has a free roll room of about less than 12%.