Piston machine with changeable displacement

US4807519A · kind A · utility

Assignee

• Mannesmann Rexroth AG · DE

Inventors

• Peter Wusthof · Lohr, DE
• Sinclair Cunningham

Key dates

• Filing date: Oct 20, 1987
• Grant date: Feb 28, 1989
• Expiry date: Oct 20, 2007

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F03C1/045
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

The invention relates to a piston machine comprising a plurality of pistons and changeable piston displacement for varying the torque and speed. The pistons are connected via control bores and distributor passages in the distributor of the machine to a high pressure and low pressure connection. To reduce the displacement a switching valve is provided via which the inactive pistons are connected together via their distributor passages and also possibly subjected to an external very low servo pressure or tank pressure. This reduces the frictional losses, increases the efficiency and avoids flow losses of the valve.