Patent ID: 7370849
Filing Date: 2008-05-13
Classification: B60G,F16F,Y10S

Abstract:
1. A self-pumping hydropneumatic spring strut unit with internal level control, the unit comprising: an oil-filled working cylinder having therein a piston dividing the cylinder into a first working space and a second working space, the piston being carried by a hollow piston rod; a high pressure chamber having therein a gas cushion which pressurizes oil in the first working space; a low pressure chamber; a piston pump driven by spring movements to transport oil from the low pressure chamber to the first working space, the pump comprising the hollow piston rod and a hollow pump rod fixed to the working cylinder, the pump rod having a distal end received in the hollow piston rod and a central bore connecting the low pressure chamber to the distal end, the bore having an upstroke valve at the distal end; a flow channel connecting the low pressure chamber to the first working space as a function of position of the working piston in the working cylinder, the flow channel extending into the piston rod coaxially to the central bore and having a deregulating opening on the first working space and a throttle toward the low pressure chamber, the deregulating opening closing as the hollow piston rod moves into the working cylinder; and a filter in the flow channel between the deregulating opening and the throttle, the filter being coaxial to the central bore.