Valve subassembly with load holding in the control spool

US10698428B2 · kind B2 · utility

Assignee

• Robert Bosch GmbH · DE

Inventor

• Steffen Knapper · Kleinglattbach, DE

Key dates

• Filing date: Feb 27, 2019
• Grant date: Jun 30, 2020
• Expiry date: Feb 27, 2039

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T137/2544
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

A valve subassembly includes a main spool having a continuously adjustable main orifice and a control spool having adjustable first and second orifices. The control spool has first and second end positions and is acted upon by a first spring toward the first end position. A fluid flow path starts from a pump and runs to an actuator via the first orifice, first control point, second orifice, second control point, main orifice, and third control point. Pressure at the first control point acts on the control spool toward the second end position and pressure at the third control point acts toward the first end position. The second orifice is closed between the first end position and an intermediate position, and opens from the intermediate position to the second end position. The second orifice opening decreases from the intermediate position to the second end position from a nonzero value to zero.