Normally Closed Steering Valve Assembly for Hydraulic Line Failure

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Solution Overview

Problem

Hydraulic systems in multi-axle steered vehicles, particularly those with booster cylinders, face the risk of pressure loss and air suction due to hose/line/pipe failures, leading to potential safety hazards and system performance degradation.

Innovation Solution

A valve assembly with normally closed valve units is implemented, which includes a first and second valve unit connected to external fluid connection elements, ensuring immediate closure upon pressure loss and providing a hydraulic shortcut to maintain system functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If normally open protection valves are used, then the valve can open automatically when pressure drops to prevent pressure loss, but the valve cannot prevent air suction into the system and hydraulic fluid loss to the environment

Engineering Contradiction:
Improvepressure loss preventionVSAvoidair suction and hydraulic fluid loss
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional valve design by using normally closed valves instead of normally open valves. The valves remain closed during normal operation and only open when intentionally activated through control ports, thereby preventing air suction and hydraulic fluid loss while still protecting against pressure loss through controlled opening.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-generated harmful factors

If normally closed valves are used, then air suction and hydraulic fluid loss are prevented, but the valve cannot automatically open to restore system functionality after a defect is resolved

Engineering Contradiction:
Improveair suction and hydraulic fluid loss preventionVSAvoidsystem recovery after defect
Core Design Contradiction:
Object-generated harmful factorsVSEase of operation

Solution Approach 1:

The patent incorporates feedback mechanisms through control ports that monitor system pressure and defect conditions. When a defect is resolved and pressure is restored, the feedback signal automatically triggers the valve to open, restoring system functionality without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The valve assembly performs self-service by automatically detecting when a defect has been resolved through pressure monitoring and autonomously opening the valve to restore hydraulic flow, eliminating the need for manual system recovery operations.

Inventive Principle:
Principle #25Self-service

3Reliability

If protection valves are installed on both ends of protected hoses, then complete protection against pressure loss is achieved, but the device complexity and number of components increase

Engineering Contradiction:
Improvecomplete protection against pressure lossVSAvoidnumber of valve units and connections
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple valve units into a single integrated valve assembly housing. The first and second valve units, along with their control ports and internal passages, are merged into one compact structure, reducing the number of separate components and simplifying installation while maintaining complete protection functionality.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The valve assembly effectively prevents hydraulic fluid loss and air suction, maintaining system integrity and functionality even in the event of hose/line/pipe failures, ensuring safe and reliable operation of the hydraulic steering system.

Implementation Method 1

a bypass valve (102) having a first inlet (102a) being connected to the hydraulic circuit and the first valve unit and a second inlet (102b) being connected to the hydraulic circuit and the second valve unit

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP4711625A1Valve assembly for a steering system, steering system and valve block
Publication Date: 2026.03.18 KB INTELLECTUAL PROPERTY GMBH & CO KG
  • EP4711625A1 patent drawingFigure 1
  • EP4711625A1 patent drawingFigure 2
  • EP4711625A1 patent drawingFigure 3

AI summary

The present invention refers to a valve assembly (100) for a steering system (1) of a vehicle, the valve assembly (100) comprising at least a first valve unit (110) and a second valve unit (120),wherein the valve assembly (100) is configured to connect a first external fluid connection (10) and a second external fluid connection (20) to a hydraulic circuit, wherein the first and second valve units (110; 120) are configured to be normally closed valves. Further, the present invention refers to a steering system (1) and a valve block (130).