Delivery flow and pressure controlling device for a hydrostatic pump

US5173031A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Gerhard Nonnenmacher · Ditzingen, DE
• Egon Tittmann
• Heinz Walter · Hergatz, DE
• Walter Robeller · Eppelheim, DE
• Dieter Bertsch · Bad Liebenzell, DE

Key dates

• Filing date: Oct 26, 1990
• Grant date: Dec 22, 1992
• Expiry date: Oct 26, 2010

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F04B49/08
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

The flow controlling device for a hydrostatic pump has a servo-piston (12) for adjusting the actuating element (11) of the adjustable pump (10) which is acted upon by a control pressure. The latter is controlled by a regulating valve (22) which is acted upon by a pressure differential across a measuring throttle (16) arranged in the delivery line (15) of the pump. Moreover, a pressure spring (23) acts on the regulating valve against the higher pressure. An external pressure supply (26) (pressurized reservoir) is provided for preparing the control pressure. To obtain an accurate, rapid flow control, even for low operating pressures, a connection line (76, 71) connecting the high-pressure side of delivery line (15) to the control pressure connector of the servo-piston (12) is provided, which contains a fixed throttle (72). Alternatively, the regulating valve may be replaced by two spatially separate valves, a flow regulator (80) and a pressure regulator (81).