Self-pumping hydropneumatic spring strut

US8091870B2 · kind B2 · utility

Assignee

• ZF FRIEDRICHSHAFEN AG · DE

Inventors

• Holger Kirchner · Ruppichteroth, DE
• Thomas Meyer · Siegburg, DE

Key dates

• Filing date: Sep 8, 2008
• Grant date: Jan 10, 2012
• Expiry date: Aug 24, 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 is provided to have internal level control. The spring strut has an outer tube having one end sealed by a piston rod guide, a working cylinder received inside the outer tube, and a hollow piston rod extending into the working cylinder through the piston rod guide. The piston rod carries a piston, which is operable to travel axially inside the working cylinder in a sealing manner and separates the working cylinder into first and second working spaces. The first working space is under a high-pressure from a high-pressure chamber and acting as a spring and the second working space is located on a piston rod-side. The spring strut also has a pump rod received inside the hollow piston rod. The pump rod and the hollow piston rod form a piston pump, which, in response to sprung movements acted thereonto, conveys a damping media from a low-pressure chamber into the first working space connected to the high-pressure chamber. The high-pressure chamber and the low-pressure chamber are each connected to the atmosphere by a filling connection formed in the piston rod guide and a check valve operable to selectively communicate the high-pressure or the l…