Lord Corporation

Michael J Chrzan

J David Carlson

Mark R Jolly

Kenneth Alan St Clair

Donald R Prindle

Douglas Edward Ivers

Lynn C Yanyo

Frank O James

Robert H Marjoram

Keith D Weiss

Theodore G Duclos

Thomas Peuker

An apparatus comprising a frame; a member movable relative to said frame; a damping device interconnected between the frame and the movable member; a controller for activating the damper to generate a damping condition at a predetermined member operating condition; and system for activating the damping device at a predetermined operating condition of the moving member during a loss of power to the apparatus. The damping device may comprise a field controllable damper that includes a volume of field controllable fluid, which may in turn comprise magnetorheological fluid for example. The rheology of the field controllable fluid is effected during the application of the field.

System and method for limiting vibration in an apparatus during a loss of power

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.

Magnetorheological twin-tube damping device

A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .phi., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .phi. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating 'rheology' changes causing restriction in flow of MR fluid (44) therethrough. In one aspect, a one-way check valve (34) is operative with a passive passageway (36) which is arranged in parallel relationship to the controllable passageway (42) provides 'asymmetric' damping across the controllable valve (18) creating higher pressure differentials in a first direction and a lower in a second direction without 'rapidly switching' the current to the coil (46). In another aspect, 'asymmetric' damping is provided by a 'changeable gap' formed by a moveable wall portion of the controllable passageway (42). In a third aspect, a first controllable passageway provides controllable flow in a first direction and a second controllable passageway provides controllable flow in a second direction, thereby provide 'asymmetry.' In a fourth aspect, 'asymmetry' is provides by a 'variable magnetic short' which changes magnetic circuit reluctance dependent on flow direction.

Two-way magnetorheological fluid valve assembly and devices utilizing

A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .PHI., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .PHI. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating 'rheology' changes causing restriction in flow of MR fluid (44) therethrough. In one aspect, a one-way check valve (34) is operative with a passive passageway (36) which is arranged in parallel relationship to the controllable passageway (42) provides 'asymmetric' damping across the controllable valve (18) creating higher pressure differentials in a first direction and a lower in a second direction without 'rapidly switching' the current to the coil (46). In another aspect, 'asymmetric' damping is provided by a 'changeable gap' formed by a moveable wall portion of the controllable passageway (42). In a third aspect, a first controllable passageway provides controllable flow in a first direction and a second controllable passageway provides controllable flow in a second direction, thereby provide 'asymmetry.' In a fourth aspect, 'asymmetry' is provides by a 'variable magnetic short' which changes magnetic circuit reluctance dependent on flow direction.

A magnetorheological fluid device which exhibits excursion (stroke or rotation) dependent resistance (force or torque) which is obtained passively. Linear and rotary embodiments are described. The devices described herein include various ways for passively varying magnetic circuit reluctance to accomplish the stroke or rotation dependent characteristic. The devices include a first component with an internal cavity, a second component received in the cavity and moveable relative to the first component, a working zone created between the first and second component, a magnetorheological fluid contained therein, at least one permanent magnet for producing a magnetic field, a magnetic circuit for directing a magnetic flux created by the permanent magnet toward the magnetorheological fluid in the working zone, and passively varying a magnetic circuit reluctance (such as by changing a thickness of a magnetic return, by changing a gap thickness, by changing the material reluctance, by interacting multiple magnetic fields, or combinations thereof) as a function of excursion. This changes the magnetic field strength acting upon the MR fluid in the working zone and produces a force/torque which varies as a function of excursion (x or .theta.).

Passive magnetorheological fluid device with excursion dependent

A controllable vibration apparatus having an electrical connection to a controllable valve made through a single-strand electrical conductor. In one embodiment, the piston and rod are preferably used as the source of ground or return electrical path. An axially compressed sealing element provides radial sealing against the conductor. An accumulator including a flexible diaphragm provides separation of fluid and accumulator chambers. In magnetorheological (MR) fluid dampers, a special sealing system including a relationship between piston rod surface finish and particle size is provided. A surface treated metal bushing is used with a lip seal to prevent escape of fluid and support side loads. The controllable valve can be formed from top and bottom pole pieces spaced from an outer ring to define a passageway. The pole and ring are preferably secured together by non-magnetic bridging elements. Preferably, the coil assembly is configured with integral axially-extending pins for ease of connection. Push-on connectors preferably make the connection between the conductor and pins. In a two single-strand conductor version, one single-strand carries the incoming current and the other the outgoing current.

Controllable vibration apparatus

Controllable composite structure or structural elements enclose magnetotheological fluids as a structural component between opposing containment layers to form at least a portion of any variety of extended mechanical systems, such as plates, panels, beams and bars or structures including these elements. The control of the stiffness and damping properties of the structure or structural elements is accomplished by changing the shear and compression/tension moduli of the magnetorheological fluid by varying the applied magnetic field. The composite structures of the present invention may be incorporated into a wide variety of mechanical systems for control of vibration and other properties.

Magnetorheological fluid composite structures

A sealless magnetorheological fluid device is disclosed in the form of an engine mount which comprises a baffle plate (58) and a solenoid type coil (40) wrapped within a housing (20). The baffle plate diverts the flow of fluid into a more intimate contact with the coil to influence the characteristics of the fluid. The mount also comprises a first chamber (94), an elastomeric element 90 bonded to an attachment collar (88) and housing (20). An elastomeric bladder (95) is bonded to a lower surface of the housing to define a second chamber (96). Orifices (98) in housing (92) operate with coil (40) to define a valve for controlling the flow of the MR fluid.

Magnetorheological fluid devices

This invention relates to sealless designs of magnetorheological fluid dampers. With these sealless designs a piston rod extends above and below a piston head within a cylindrical housing and has frustoconical elastomer elements attached to and between the rod and housing to allow translation of the piston head and rod. The piston head has a coil contained radially therein that produces magnetic flux in and around the piston. The advantages of utilizing an MR fluid according to the invention include magnetic fields which are easily produced by low voltage electromagnetic coils, damping effects which are velocity independent, and higher yield strength obtained by the MR fluid capable of generating greater damping forces.

Magnetorheological (MR) fluid dampers are optimized. Dimensional relationships involved in the flow of magnetic flux are related to an operational parametric ratio of magnetic flux density in the fluid to the flux density in the steel. A magnetic valve is utilized to change the flow parameters of the MR fluid and, hence, the operational characteristics of the damper. Several embodiments depicting improved piston designs, including spool as well as toroidal configurations, are disclosed. In addition, both single and twin-tube housing designs are presented.

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Apex, NC, United States of America

Michael J Chrzan