Patent ID: 8235186

Claim:
A hydraulic damper spool valve for a hydraulic damper, comprising: a valve sleeve providing an internal cylindrical bore, and an external cylindrical surface, a sharp edged land feature, and a first effective piston area; a cylindrical valve spool having an open end, a closed end defining a second effective piston area, and a shaped aperture defined in a wall of the valve spool; the valve sleeve being adapted to accept the valve spool with a predetermined, close tolerance radial clearance that is configured to allow longitudinal movement of the valve spool within the internal cylindrical bore of the valve sleeve while preventing hydraulic flow through the radial clearance; a valve body having a first chamber and a second chamber interconnected via a cylindrical passage, the cylindrical passage being adapted to accept the valve sleeve with a predetermined, close tolerance radial clearance that is configured to allow longitudinal movement of the valve sleeve within the cylindrical passage while preventing hydraulic flow through the radial clearance; the valve body affixed to the damper's main piston, the valve body defining a first passage that provides an unobstructed hydraulic path between an upper portion of the hydraulic damper and the first chamber and a second passage that provides an unobstructed hydraulic path between a lower portion of the hydraulic damper and the second chamber; a resilient energy storage member arranged between the valve sleeve and valve spool so as to bias the valve sleeve and valve spool in an opposing direction to a force vector generated by the operating pressures in the damper's hydraulic fluid; whereby the main piston is configured to move in a first direction and the operating pressure generated in the damper's hydraulic fluid acts upon the first effective piston area and induces longitudinal movement of the valve sleeve against a biasing force of the resilient energy storage member causing the sharp edged land feature to move relative to the shaped aperture thereby varying fluid flow through the varying exposed, open shaped aperture, and when the hydraulic damper's main piston moves in a second direction the operating pressure generated in the damper's hydraulic fluid acts upon the second effective piston area and induces longitudinal movement of the valve spool against a biasing force of the resilient energy storage member causing the shaped aperture to move relative to the sharp edged land feature varying the fluid flow through the varying exposed, open area of the aperture.