Patent ID: 7753179
Filing Date: 2010-07-13
Classification: B60G,F16F

Abstract:
1. A suspension unit including: an accumulator for holding and maintaining a fluid under pressure, and a motion damping means, said accumulator having a floating piston that sealingly separates a first chamber for storing a pressurized gas and a second chamber for storing said fluid under pressure; said motion damping means including a third chamber, that is fluid-filled in operation, in fluid flow communication with said second chamber of said accumulator, said motion damping means having valve means separating said second chamber from said third chamber for permitting a controlled flow of said fluid between said second and third chambers via shimmed valve ports; wherein said accumulator and said motion damping means are capable of relative retracting and extending movement during which fluid is forced through said valve means at respective predetermined controlled rates so as to dampen the relative movement during retraction or extension; said relative movement when said accumulator and said motion damping means relatively extend, cause fluid to flow from said second chamber of the accumulator through the valve means to said third chamber of said motion damping means, whereby gas pressure in said first chamber moves said floating piston in said accumulator thereby reducing the gas pressure in said first chamber, and when said accumulator and said motion damping means relatively retract, fluid is caused to flow from said third chamber of said motion damping means through the valve means to said second chamber of said accumulator, thereby increasing the fluid pressure therein and moving said floating piston to increase the pressure of the gas in said first chamber; wherein said suspension system further includes: a side chamber within said motion damping means about said accumulator, wherein said side chamber respectively expands and contracts with said relative retracting and extending movement of said accumulator and said motion damping means; and at least one bleed port communicating said side chamber with said second chamber, the bleed port restricting the flow of fluid between the side chamber and the second chamber thereby assisting control of the relative movement of the accumulator and said motion damping means wherein said valve means is a flooder valve allowing fluid to flow through said valve in two different directions, the valve means having peripheral ducts in fluid one way communication during retraction only with said third chamber and said side chamber, of a different size to said valve ports in fluid communication with said third chamber and said second chamber such that the rate of flow of fluid through said valve means from the second chamber to the third chamber under predetermined extending forces differs from the rate of flow of fluid through said valve means from the third chamber to the second chamber under similar retracting forces, wherein said side chamber has a non return valve arrangement whereby fluid passes directly from said third chamber to said side chamber during retraction and via said second chamber and associated bleed port during extension.