Adjustment mechanism for radial-piston pump

US4077745A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Werner Rometsch · Gerlingen, DE
• Horst Willmer

Key dates

• Filing date: Feb 10, 1977
• Grant date: Mar 7, 1978
• Expiry date: Feb 10, 1997

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F04B1/07
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A pump has a rotatable rotor carrying a plurality of radially-extending pistons bearing at their outer ends on an annular adjustment ring which can be displaced radially in the pump housing by means of a pair of diametrically opposed adjustment cylinders that serve to displace this ring and adjust the stroke of the radial pistons in the rotor. One of the adjustment pistons is of larger diameter than the other and both of the adjustment pistons are spring-biased against the outer periphery of the adjustment ring and both have throughgoing bores so that pressure behind these adjustment pistons is fed to pressure-relief pockets at their inner ends against the adjustment ring. The small-diameter piston is provided in its through-going passage with a pressure-limiting valve which only allows pressure past to its respective pressure-relief pocket when pressure behind the smaller piston exceeds a predetermined minimum which is approximately a tenth of the maximum pump operating pressure. Thus during starting-up of the pump the pressure-relief pocket at the small piston is not pressurized to increase friction between the inner end of this piston and the adjustment ring so as to inhibit rot…