Electrohydraulic drive

US5875632A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Andreas Kappel · Höhenkirchen-Siegertsbrunn, DE
• Randolf Mock · Munich, DE

Key dates

• Filing date: May 30, 1997
• Grant date: Mar 2, 1999
• Expiry date: May 30, 2017

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02M51/0603
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

An electrohydraulic drive is provided. High-speed injection valves of hydraulic lift transformers have, for example, a pressure piston driven by a piezoelectric actuator and a reciprocating piston mounted in an axially displaceable fashion in a pressure piston bore and connected to the valve needle. The electrohydraulic drive has a piezoelectric actuator and a hydraulic force/travel transmission of compact design. To ensure the required axial symmetry of the drive despite production-induced tolerances, a balance element supported in a frustoconical depression of the pressure piston is arranged between the piezoelectric actuator and the lift transformer. During assembly of the hydraulics, the element having the form of a spherical segment and produced from high-grade steel can slide freely on the piezoceramic and thus compensate a nonconcentric alignment of the actuator and pressure piston. The ability to rotate freely inside the abutment ensures that the upper part of the actuator always bears with the full surface contact against the pressure piston.