Linear Actuator Multi-Degree Freedom Mounting Structure

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Solution Overview

Problem

Existing mounting schemes for linear actuators in aircraft propulsion systems face limitations in accommodating slight misalignments and non-axial movements without transmitting lateral loads, which can lead to inefficiencies and potential damage.

Innovation Solution

A multi-degree of freedom mounting structure incorporating spherical bearings and pivotally coupled links that allow for parallel centerlines to the actuation axis, enabling slight rotations and radial movements while maintaining axial load transmission, and featuring a gimbal joint configuration to accommodate skewed orientations without imparting lateral loads on the linear actuator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid mounting structure is used to ensure stable axial load transmission, then load transmission efficiency is improved, but the structure cannot accommodate misalignments and non-axial movements, leading to lateral load transmission and potential damage

Engineering Contradiction:

Improveaxial load transmission stabilityVSAvoidaccommodation of misalignment and non-axial movement

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The mounting structure is divided into multiple independent spherical bearing assemblies, each capable of accommodating movement in multiple degrees of freedom. This segmentation allows each bearing to independently handle misalignments while the collective assembly maintains stable axial load transmission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Spherical bearings are used instead of rigid cylindrical joints. The spherical geometry allows each bearing to rotate and tilt within its mounting assembly, accommodating non-axial movements and misalignments in multiple directions while still transmitting axial loads effectively.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If spherical bearings with multiple degrees of freedom are used to accommodate misalignments, then adaptability is improved, but the structural rigidity and load transmission efficiency may be compromised

Engineering Contradiction:

Improveaccommodation of misalignment and non-axial movementVSAvoidaxial load transmission stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The mounting structure segments the load path through multiple spherical bearings arranged in series, where each bearing handles a portion of the movement accommodation while the overall structure maintains axial load transmission integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each spherical bearing assembly serves multiple functions simultaneously: accommodating misalignments, allowing non-axial movements, and transmitting axial loads. This multi-functionality is achieved through the universal spherical joint design that handles both movement compensation and load bearing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a complex multi-degree of freedom mounting structure is used to accommodate all movements, then adaptability is improved, but device complexity increases

Engineering Contradiction:

Improveaccommodation of misalignment and non-axial movementVSAvoidnumber of components and mounting elements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple spherical bearings are integrated into a single mounting structure assembly that functions as one unified component. This merging reduces the number of separate mounting elements needed while maintaining the multi-degree of freedom capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mounting structure is designed as a universal joint assembly where each spherical bearing can accommodate movements in multiple directions. This universal design eliminates the need for separate specialized joints for different movement types, reducing overall complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution effectively allows for slight misalignments and rotations while ensuring that only axial loads are transmitted, reducing the risk of damage and maintaining efficient operation of the linear actuator, even when components move in opposite circumferential or radial directions.

Implementation Method 1

a first spherical bearing and a second spherical bearing... a third spherical bearing and a fourth spherical bearing

Methodology Applied

Scientific EffectSpherical bearing: Ball

Implementation Method 2

The first link may be pivotally coupled to the first mount about a fourth pivot axis perpendicular to the first pivot axis and the actuation axis

Methodology Applied

Scientific EffectPivotal coupling: Hinge

Data Source

PatentEP3301326B1Linear actuator with multi-degree of freedom mounting structure

Publication Date: 2020.11.18 ROHR INC

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AI summary

An actuation system includes a linear actuator (28) extending longitudinally along an actuation axis (30). A first link (56A) extends along a first centerline parallel to the actuation axis (30), where the first link (56A) is on a first side of the linear actuator (28). A second link (56B) extends along a second centerline parallel to the actuation axis (30), where the second link (56B) is on a second side of the linear actuator (28). The first and the second links (56A, B) are configured to transfer a load along the first and the second centerlines between the component (25) and the linear actuator (28).