Damping valve unit for a hydraulic oscillation damper

US4993524A · kind A · utility

Assignee

• Fichtel & Sachs · DE

Inventors

• Manfred Grundei · Niederwerrn, DE
• Hans Reimer · Waigolshausen, DE

Key dates

• Filing date: Nov 22, 1989
• Grant date: Feb 19, 1991
• Expiry date: Nov 22, 2009

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16F9/348
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

According to an illustrative example of this invention, the piston of a hydraulic oscillation damper is provided with a traction valve, i.e. a valve which is intended to damp the outward movement of the piston rod. This traction valve includes two valve discs and a valve member. The valve member is biased towards a closed position and urges the valve discs against a valve face of the piston. In response to a predetermined pressure difference between the two working chambers on both sides of the piston, a flow passage is opened by lifting the valve discs and the valve member from the valve face. Below said predetermined pressure difference, a preliminary restricted flow passage exists. This preliminary restricted flow passage extends in series across the radially inner circumferential edge of a first valve disc adjacent to the piston and through radially inner edge recesses and through radially outer edge recesses of a second valve disc adjacent to the first valve disc. A first liquid flow resistance is established by the radially inner edge recesses, and a second liquid flow resistance is established by the radially outer edge recesses. The first liquid flow resistance is larger th…