Spool Valve Load Damping for Aircraft Nose Gear Steering

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing hydraulic steering system control circuits for aircraft are complex and costly to manufacture and maintain, and they do not effectively address the dynamic load damping needs of aircraft nose gear steering systems.

Innovation Solution

A dynamic load damping apparatus with a simplified construction, featuring a spool valve and a sleeve within a circuit housing, which reduces manufacturing costs and improves load control on aircraft steering systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple valves and complex control circuits are used to dampen dynamic loads, then load control effectiveness is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveload control effectivenessVSAvoidcircuit construction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple valve functions into a single integrated spool valve with multiple lands (first, second, and third lands) that perform load damping, pressure regulation, and flow control functions simultaneously. This merging of functions reduces the number of separate components while maintaining effective load control.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spool valve is designed as a multi-functional component where different lands perform different functions: the first land controls load damping, the second land regulates pressure, and the third land manages flow distribution. This universal design allows one component to replace multiple specialized valves.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple valves and complex control circuits are used to dampen dynamic loads, then load control effectiveness is improved, but manufacturing cost increases

Engineering Contradiction:
Improveload control effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By integrating multiple valve functions into a single spool valve assembly, the patent reduces the total number of parts that need to be manufactured, assembled, and quality-tested. This consolidation directly reduces manufacturing costs while maintaining load control effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If multiple valves and complex control circuits are used to dampen dynamic loads, then load control effectiveness is improved, but maintenance difficulty and cost increase

Engineering Contradiction:
Improveload control effectivenessVSAvoidmaintenance difficulty
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The integrated spool valve design reduces the number of potential failure points and simplifies the maintenance process. Instead of troubleshooting and potentially replacing multiple separate valves, maintenance personnel only need to service a single integrated component, reducing maintenance time and expertise requirements.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If a simplified construction with a single spool valve is used, then manufacturing cost is reduced, but load damping effectiveness may be compromised

Engineering Contradiction:
Improvemanufacturing costVSAvoidload damping effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The spool valve incorporates locally differentiated features with each land having specific geometries and positions optimized for its function. The first land is configured for load damping, the second for pressure regulation, and the third for flow control, ensuring that each local region of the single component performs its specific function effectively.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes changes in spool valve position and land exposure to dynamically adjust hydraulic parameters (flow rate, pressure, directional control) in response to varying load conditions, enabling a single component to effectively handle a wide range of damping requirements.

Inventive Principle:
Principle #35Parameter changes

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 dynamic load damping apparatus effectively reduces the cost of manufacturing hydraulic steering system control circuits while improving the stability and control of aircraft nose gear steering systems by efficiently managing dynamic loads.

Implementation Method 1

a first restricted conduit extending across the spool valve and providing fluid communication between the first groove and the first portion of the interior bore

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

The first restricted conduit may extend across the exterior surface of the first land, or may extend through the first land

Methodology Applied
Scientific EffectFluid flow restriction: Pressure Drop

Data Source

PatentEP3919756B1Dynamic load damping apparatus
Publication Date: 2025.04.09 THE BOEING CO
  • EP3919756B1 patent drawingFigure 1
  • EP3919756B1 patent drawingFigure 2
  • EP3919756B1 patent drawingFigure 3

AI summary

A dynamic load damping apparatus is employed in a hydraulic steering system control circuit of an aircraft. The dynamic load damping apparatus is positioned in the hydraulic steering system control circuit in parallel with a control valve of the control circuit that functions as the hydraulic fluid source of the control circuit and an actuator that controls movements of a nose gear of the aircraft. The dynamic load damping apparatus dampens loads transmitted to the hydraulic actuator that controls the steering movements of the nose gear on the aircraft.