Abstract: The piston for a magneto-rheological fluid system is manufactured from a piston skirt of a material having a high magnetic permeability and a piston plate which closes one end of the piston skirt having a low magnetic permeability and therefore must be made out of a material such as stainless steel. The piston is manufactured by placing the plate on one electrode and clamping another set of electrodes against the outer circumferential surface of the piston ring or skirt. The plate and ring are brought into contact with one another while applying a current through the piston ring and the piston plate, thereby heating interfering portions of the ring and plate and permitting the plate to be forced inside of the ring while at the same time allowing the softened or plastic portions of the ring and plate to intermingle with one another and thus form a solid state bond.

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 rotary damper for use in an automotive vehicle. The rotary damper includes an outer casing having a main chamber and a pair of piston orifices, the main chamber and the piston orifices being filled with a damping fluid, a pivotable cam located in the main chamber and attached to an arm for transferring the rotary movement of the arm to the cam. The damper also includes a pair of pistons, each located in its own orifice, and connected to opposite sides of the cam. When the arm transfers the rotary movement to the cam, each piston is moved in opposite directions in its respective piston orifice to damp the rotary movement of the arm.

Abstract: The piston for a magneto-rheological fluid system is manufactured from a piston skirt of a material having a high magnetic permeability and a piston plate which closes one end of the piston skirt having a low magnetic permeability and therefore must be made out of a material such as stainless steel. The piston is manufactured by placing the plate on one electrode and clamping another set of electrodes against the outer circumferential surface of the piston ring or skirt. The plate and ring are brought into contact with one another while applying a current through the piston ring and the piston plate, thereby heating interfering portions of the ring and plate and permitting the plate to be forced inside of the ring while at the same time allowing the softened or plastic portions of the ring and plate to intermingle with one another and thus form a solid state bond.

Abstract: A suspension damper includes a reservoir housing with a piston slidably mounted therein and including a piston rod extending from the reservoir housing and attached to the vehicle by a mount assembly. An air chamber is defined by a sleeve cirucmscribing the piston rod and connected to the reservoir housing by a flexible portion. The mount assembly includes a pumping chamber which expands and contracts in response to normal road undulations to inflate the air chamber. A valve controlled by the flexible portion of the sleeve controls communication from the air chamber to ambient atmosphere to thereby control inflation of the air chamber and thereby controlling ride height.

Abstract: The piston for a magneto-rheological fluid system is manufactured from a piston skirt of a material having a high magnetic permeability and a piston plate which closes one end of the piston skirt having a low magnetic permeability and therefore must be made out of a material such as stainless steel. The piston is manufactured by placing the plate on one electrode and clamping another set of electrodes against the outer circumferential surface of the piston ring or skirt. The plate and ring are brought into contact with one another while applying a current through the piston ring and the piston plate, thereby heating interfering portions of the ring and plate and permitting the plate to be forced inside of the ring while at the same time allowing the softened or plastic portions of the ring and plate to intermingle with one another and thus form a solid state bond.

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: 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 variable load limiting restraint retractor for a seat restraint system in a vehicle includes a housing for operative connection to vehicle structure. The variable load limiting restraint retractor also includes a take-up spool operatively connected to the housing and connected to a belt of a seat restraint system for winding and unwinding the belt. The variable load limiting restraint retractor includes a rotatable shaft operatively connected to the take-up spool and the housing, the take-up spool being mounted on the shaft. The variable load limiting restraint retractor further includes a load limiting assembly operatively connected to the shaft for variably limiting load on the belt when the seat restraint system is in a buckled position.

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: A suspension damper includes a reservoir housing with a piston slidably mounted therein and including a piston rod extending from the reservoir housing and attached to the vehicle by a mount assembly. An air chamber is defined by a sleeve cirucmscribing the piston rod and connected to the reservoir housing by a flexible portion. The mount assembly includes a pumping chamber which expands and contracts in response to normal road undulations to inflate the air chamber. A valve controlled by the flexible portion of the sleeve controls communication from the air chamber to ambient atmosphere to thereby control inflation of the air chamber and thereby controlling ride height.

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 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 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 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 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: 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%.

Abstract: The piston for a magneto-rheological fluid system is manufactured from a piston skirt of a material having a high magnetic permeability and a piston plate which closes one end of the piston skirt having a low magnetic permeability and therefore must be made out of a material such as stainless steel. The piston is manufactured by placing the plate on one electrode and clamping another set of electrodes against the outer circumferential surface of the piston ring or skirt. The plate and ring are brought into contact with one another while applying a current through the piston ring and the piston plate, thereby heating interfering portions of the ring and plate and permitting the plate to be forced inside of the ring while at the same time allowing the softened or plastic portions of the ring and plate to intermingle with one another and thus form a solid state bond.

Abstract: Parallel paths for damping fluid are provided through the piston of a suspension damper, each of which are provided with separate damping valving sets to control damping. Communication through one of the paths is controlled by a movable control valve member, which is controlled by a magnetostrictive element which deforms in response to application of a magnetic field. The control valve member is moved between active and inactive positions in response to changes in a magnetic field applied by a coil mounted within the damper piston. In one position, all communication of damping fluid is through one of the damping valve sets, while in the other positon damping fluid communicates through both valve sets. Accordingly, damping levels may be varied by controlling the magnetic field.

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.