Patent ID: 7364022
Filing Date: 2008-04-29
Classification: F16F

Abstract:
1. A motion-damping device having a movable piston, comprising: a first valving stage comprising a first primary valving region defining a first passageway having a first height coupled to a first secondary valving region defining a second passageway having a second height, wherein a first valve plate is positioned between the first primary valving region and the first secondary valving region; a second valving stage in series with the first valving stage, the second valving stage comprising a second primary valving region defining a third passageway having a third height coupled to a second secondary valving region defining a fourth passageway having a fourth height, wherein a second valve plate is positioned between the second primary valving region and the second secondary valving region; first, second and third orifices coaxially aligned with the movable piston, wherein the first orifice has a first diameter and is communicable in fluid flowing communication with the first primary valving region, the second orifice has a second diameter and is communicable in fluid flowing communication with the first secondary and second primary valving regions, and the third orifice has a third diameter and is communicable in fluid flowing communication with the second secondary valving region; a magneto-rheological fluid (MRF) contained in the first and second primary valving regions and the first and second secondary valving regions in a manner allowing the MRF to flow through said valving regions; a first magnet configured to produce a magnetic field within at least one of the first primary valving region and the first secondary valving region; and a second magnet configured to produce a magnetic field within at least one of the second primary valving region and the second secondary valving region; wherein motion of the piston is damped by the flow of MRF through the first primary and secondary valving regions and the second primary and secondary valving regions as the first and second magnets produce their respective magnetic fields, and wherein a first ratio of the first height and the first diameter, a second ratio of the second height and the second diameter, a third ratio of the third height and the second diameter, and a fourth ratio of the fourth height and the third diameter are each greater than approximately 0.3.