Nose-Wheel Steering Gear Layout for Compact Strut Integration

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Solution Overview

Problem

Aircraft nose-wheel steering systems are bulky and difficult to accommodate when not in use, and alignment and mechanical balancing of the strut and rack can be challenging, making them hard to support effectively.

Innovation Solution

A nose-wheel steering system with a gearing mechanism that includes a steering collar, idler gear, and pinion with a first gear and second gear of different radii, along with a hydraulic actuator and integrated manifold for fluid control, allowing for compact design and precise hydraulic control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional axially translatable toothed rack is used for nose-wheel steering, then the steering function is achieved, but the system becomes bulky and difficult to accommodate when not in use

Engineering Contradiction:
Improvesteering functionVSAvoidsystem size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The steering system is divided into modular components: a strut assembly with integrated steering mechanism, a separable rack, and independent mounting structures. This segmentation allows the system to be compact when not in use while maintaining full steering functionality during operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rack is reoriented from traditional axial translation to a different dimensional arrangement where it can be stored in a compact configuration and deployed for steering when needed. The gearing mechanism enables the rack to function in a space-efficient orientation that reduces overall system volume

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a traditional rack and pinion arrangement is used, then steering is achieved, but alignment of the strut and rack becomes difficult

Engineering Contradiction:
Improvesteering controlVSAvoidalignment complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The steering mechanism is merged directly into the strut assembly, with the pinion and gearing mechanism integrated into the strut structure. This integration eliminates the need for separate alignment procedures between the strut and rack, as they are designed to work together as a unified assembly

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The gearing mechanism acts as an intermediary between the rack and the nose-wheel, providing a buffer that accommodates minor misalignments and reducing the precision requirements for strut-rack alignment. This intermediate transmission system makes the overall alignment process more forgiving and easier to achieve

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If a traditional rack and pinion arrangement is used, then steering is achieved, but mechanical and hydraulic balancing of the actuator becomes difficult

Engineering Contradiction:
Improvesteering controlVSAvoidbalancing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The hydraulic actuator is merged with the steering mechanism in a unified assembly where the actuator directly drives the pinion or rack. This integration simplifies the balancing requirements by eliminating separate mounting and connection points that would otherwise require complex mechanical and hydraulic alignment

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator assembly is designed to be self-balancing through its integrated structure, where the mechanical components and hydraulic system are configured to automatically achieve proper balance during installation without requiring complex external adjustment procedures

Inventive Principle:
Principle #25Self-service

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 system achieves a compact design and precise steering control, enabling efficient aircraft maneuverability while reducing the complexity of alignment and balancing issues, thus improving storage and operational efficiency.

Implementation Method 1

the actuator includes a first hydraulic chamber configured to translate the rack in a first direction. In various embodiments, the actuator includes a second hydraulic chamber configured to translate the rack in a second direction

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP3862265B1Nose wheel steering system
Publication Date: 2023.05.03 GOODRICH CORP
  • EP3862265B1 patent drawingFigure 1
  • EP3862265B1 patent drawingFigure 2
  • EP3862265B1 patent drawingFigure 3A

AI summary

A nose-wheel steering system (200) is disclosed. In various embodiments, the system includes an actuator (202); a strut (204); and a gearing mechanism (206) operably coupling the actuator (202) to the strut (204), the gearing mechanism (206) including a steering collar (216) attached to the strut (204), and idler gear (218) engaged with the actuator (202) and a pinion (210) having a first gear (212) engaged with the idler gear (218) and a second gear (214) engaged with the steering collar (216).