Abstract: A decoupled mono tube damper assembly for a vehicle includes an outer tube attached to the vehicle's unsprung mass. The outer tube has a base and a sleeve end. An outer tube sleeve engaging end of an inner tube is slidingly engaged with the sleeve end. The inner tube has an end distal to the sleeve engaging end, and is attached to the vehicle's sprung mass at the distal end. A damper rod has one opposed end extending axially into a base aperture, and an opposed end connecting to the inner tube. The rod moves axially relative to the outer tube, due to forces transmitted from the unsprung mass. A low amplitude energy-managing member is operatively disposed within the outer tube, and has a throughbore receiving the rod. A travel-limiting member attaches to the rod and is engageable with the energy-managing member. The travel-limiting member constrains axial movement of the rod through the outer tube base to a predetermined limit.

Abstract: The ability of a damper to attenuate smooth road shake in a vehicle is tested using a test fixture that is controlled by inputting data for periodic low amplitude periodic excitations having a selected frequency range, selected amplitude range and a selected dither representative of vehicle operation on relatively smooth roads. The selected frequency range is about 5 Hz to 30 Hz and the selected amplitude range is about 0.05 mm to 2.00 mm. A preferred frequency is about 15 Hz which is applied preferably for about 200 cycles in a series of separate tests at individual amplitudes of, for example, 0.05, 0.10, 0.15, 0.20, 0.25, 0.50, 1.00 and 2.00 mm. The damper is tested to produce low amplitude test results comprising displacement, force and velocity parameters, measured as functions of time.

Abstract: Dampers for vehicle suspensions include a housing comprising a tube attached to a wheel axle of a vehicle and a piston rod extending from a piston within the tube and attached to the vehicle body. The piston divides the tube into first and second chambers. In order to damp responses when minor smooth road imperfections impart low force excitations to the wheel of the vehicle, a fluid bypass passageway in the form of a sleeve is positioned around the tube and overlies the piston. This provides second stage quasi-ideal damping at low force excitations to the wheels and thus to the wheel axles of the vehicle. The sleeve communicates with the first and second chambers through metered orifices or valves. As low force excitations from smooth road imperfections displace fluid within the tube through the metered orifices or valves, the orifices damp responses to the low force excitations, thereby smoothing the ride of the vehicle.