Patent ID: 7422199

Claim:
A self-pumping hydropneumatic suspension strut unit with internal level control, the suspension strut unit comprising: an oil filled working cylinder having an end which is closed by an end wall and another end which is fitted with a rod guide; a damping piston which is free to slide in the working cylinder, the piston being connected to a hollow piston rod extending from the rod guide; a pump rod extending into the hollow piston rod to form a pump cylinder, the pump rod having an end received in the end wall and a circumferential groove proximate to the end, the groove having a width and a bottom with a diameter; and a disk having an outer circumference which is held between the working cylinder and the end wall, and a slot which receives the pump rod, the slot having a first portion with a diameter which corresponds to the diameter of the bottom of the groove and a second portion with a diameter which corresponds to the outside diameter of the pump rod, the disk being formed as a Belleville washer having a conical shape in an unloaded condition, the disk being pressed into a loaded condition by the working cylinder bearing against the outer circumference, wherein the disk has a flat central portion and a surrounding portion which extends conically from the central portion to the circumference when the disk is in an unloaded condition, the surrounding portion being pressed flat when the disk is in a loaded condition.