Self-pumping hydropneumatic spring strut

US8052128B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Holger Kirchner · Ruppichteroth, DE
• Hubert Beck · Eitorf, DE
• Thomas Meyer · Siegburg, DE

Key dates

• Filing date: Sep 8, 2008
• Grant date: Nov 8, 2011
• Expiry date: Aug 4, 2030

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S267/02
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A self-pumping hydropneumatic spring strut with internal leveling control, particularly for motor vehicles, has an outer tube having an oil-filled high-pressure work space in the work cylinder, which high-pressure work space is under pressure by at least one gas cushion which is arranged in a high-pressure chamber and acts as a spring, a second work space on the piston rod side, and a piston which is supported by a hollow piston rod and which is axially displaceable in the work cylinder in a sealed manner, a piston pump which is driven by the spring movement of the vehicle and pumps oil out of a low-pressure chamber into the work space connected to the high-pressure chamber and which comprises a pump rod and a pump cylinder which is formed by the hollow piston rod, and the high-pressure chamber can be connected to the atmosphere by a flow connection which is arranged in the piston rod guide and has a closing element. The piston rod is sealed in the piston rod guide by means of at least two seals which are arranged one behind the other axially. A flow connection extends from between two adjacent seals into the low-pressure chamber. The flow connection is acted upon by a check valve …