Electrohydraulic pressure supply unit with variable-displacement pump and controllable electric device

US6347516B1 · kind B1 · utility

Assignee

• Daimlerchrysler AG · US

Inventors

• Gerald Bolz · Berlin, DE
• Michael Jürging · Kelkheim, DE
• Reinhard Orthmann · Leonberg, DE

Key dates

• Filing date: Jun 30, 2000
• Grant date: Feb 19, 2002
• Expiry date: Jun 30, 2020

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F04B2205/09
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

An electrohydraulic pressure supply unit involving the joint operation of two energy converters, which can be adjusted independent of each other, including an electric motor with speed control that drives a variable displacement pump with a variable displacement volume. The electric motor converts electrical output (loss-encumbered), into mechanical output, meaning into speed n and torque T. The pump then converts this mechanical output (also loss-encumbered) into hydraulic output. The hydraulic output is determined by the pressure difference &Dgr;p across the pump and the volume flow Q. The pressure difference &Dgr;p generally is impressed by the consumer or load on the system. The volume flow Q is the result of the displacement volume V and the motor speed n. The torque T, which must be generated by the motor, is derived from the displacement volume V and the pressure differential &Dgr;p. During the conversion from hydraulic output to mechanical output, the displacement volume V determines the distribution of the output to the speed n of the motor and the torque T. The current I flowing through the electric motor is primarily determined by the torque T while the voltage U is prim…