Self pumping, hydropneumatic, telescopic, spring damping device with internal level regulation

Claim 1

A self-pumping, hydropneumatic, telescopic, spring damping device with internal level regulation, especially for automotive vehicles, comprising: a working cylinder with an oil filled working chamber and a working piston slidably borne therein and provided with damping devices, said working piston being carried at the end of a hollow piston rod that passes sealingly from the working cylinder, a gas cushion in a gas spring chamber which is connected with the working chamber and which pressurizes the oil in the working chamber, an oil reservoir chamber defined by an outer jacket tube which encloses the working chamber and has a free surface between oil and gas in the reservoir, a hollow pump rod elastically borne on a partition, which pump rod is communicated at one end with the oil reservoir chamber below the surface of the oil, said pump rod at its other end having a pump suction valve and cooperating with a pump chamber disposed in the hollow piston rod for level regulation, such that as a function of the in and out spring motions oil is delivered from the oil reservoir chamber into the working chamber, a control opening in the pump rod such that, when the desired oil level is exceeded, oil can flow from the work chamber into the oil reservoir chamber via the control opening, a pump discharge valve disposed on the end of the pump chamber which is remote from the partition, said pump discharge valve being located in a control sleeve located in a piston rod cavity between the piston rod and the pump rod, said control sleeve forming passages which lead from a pump outlet valve to the working chamber, the end of said control sleeve toward said partition forming a control edge for said control opening, and a separating body of solid material movably disposed in the gas spring chamber in the region of the interface between the oil and gas, said device being characterized in that said separating body of solid material comprises a separating piston guided by a seal at its periphery in said gas spring chamber, said gas spring chamber being connected axially to the working chamber in the region of said partition which bears the pump rod and being communicated with said work chamber via at least one passage in said partition, the partition itself in the region of the working chamber being elastic, a pump suction tube fluidly communicating a pump rod cavity with the oil reservoir chamber below the surface of the oil, said pump suction tube being constructed and arranged so as to be yieldable with respect to movements of said partition, and said separating piston presenting a recess on its face toward said partition, in which recess, upon disposition of the separating piston in the region of the partition, the pump suction tube can be received.