Patent ID: 6161662
Filing Date: 2000-12-19
Classification: F16F

Abstract:
A monotube suspension damper for a motor vehicle including:a cylinder tube having a gas cup therein dividing the cylinder tube into a gas-filled gas chamber and a fluid-filled fluid chamber,a piston supported in the cylinder tube for back and forth linear translation and dividing the fluid chamber into a compression chamber facing the gas cup and a rebound chamber on the opposite side of the piston from the compression chamber,a piston rod supported on the cylinder tube for back and forth linear translation having an inboard end connected to the piston for linear translation as a unit therewith and an outboard end outside of the cylinder tube,a passage means operative to define a primary fluid flow path across the piston between the compression chamber and the rebound chamber and a secondary fluid flow path across the piston parallel to the primary fluid flow path, anda throttling valve means operative to throttle fluid flow through each of the primary and the secondary fluid flow paths during a rebound stroke of the suspension damper without significantly obstructing fluid flow through each of the primary and the secondary fluid flow paths during a compression stroke of the suspension damper,characterized in that the suspension damper further comprises:a valve means on the piston having a closed position blocking the secondary fluid flow path and an open position unblocking the secondary fluid flow path, anda control means operative in response to an increasing pneumatic pressure in an expansible pneumatic load leveling chamber between a sprung mass of the motor vehicle and an unsprung mass of the motor vehicle to actuate the valve means from the open position thereof to the closed position thereof thereby to increase the stiffness of the suspension damper as the pneumatic pressure in the expansible pneumatic load leveling chamber increases.