Flexible Coupling Lattice Design for Stress Reduction

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Solution Overview

Problem

Conventional flexible couplings face challenges in managing stress caused by misalignment between interconnected shafts, as they often rely on geometric adjustments that may not adequately distribute torque and misalignment stress effectively.

Innovation Solution

A flexible coupling design featuring a flex beam member with a rounded cross-sectional area, interconnected by spar members and interconnect members with saddle-shaped profiles, which reduces peak stress through a lattice structure that accommodates both axial and angular misalignments, and is manufactured using additive techniques for enhanced flexibility and rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If conventional planar discs with necked profiles are used to accommodate shaft misalignment, then misalignment stress is managed, but peak stress concentrations occur at the necked regions

Engineering Contradiction:

Improvepeak stressVSAvoidstress concentration

Core Design Contradiction:

Stress or pressureVSStrength

Solution Approach 1:

The patent applies curvature by replacing the conventional necked profile with a rounded cross-sectional area throughout the flex beam member. This rounded geometry eliminates sharp transitions and stress concentration points, allowing the member to flex and accommodate misalignment while distributing stress more uniformly across the structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If multiple joints and connections are used in conventional couplings to accommodate misalignment, then flexibility is achieved, but device complexity and weight increase

Engineering Contradiction:

Improvemisalignment accommodationVSAvoidnumber of joints

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple separate components (flex beams, spars, and interconnect members) into an integrated lattice structure. This unified design achieves the necessary flexibility and misalignment accommodation through the overall geometry and material properties rather than through multiple discrete joints and connections.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lattice structure employs varying member thicknesses and cross-sectional areas at different locations to optimize flexibility and strength where needed. The rounded cross-sectional areas are strategically positioned to provide local flexibility while maintaining overall structural integrity.

Inventive Principle:

Principle #3Local quality

3Shape

If conventional manufacturing methods are used for couplings with complex geometries, then structural features can be produced, but manufacturing precision and cost are adversely affected

Engineering Contradiction:

Improverounded cross-sectional areaVSAvoidgeometric accuracy

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The patent utilizes additive manufacturing technology, which enables the production of complex rounded geometries with high precision. This manufacturing method allows for continuous curved surfaces and varying cross-sectional areas that would be difficult or expensive to produce using conventional subtractive or forming methods.

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

This design effectively transfers torque while minimizing stress concentrations, accommodating misalignments and reducing the need for joints, resulting in a lightweight, cost-effective, and robust coupling solution with improved tolerance for rotational misalignments.

Implementation Method 1

The flex beam member has a rounded cross-sectional area to reduce peak stress in the flex beam member due to misalignment between the input body and the output body while transferring torque

Methodology Applied

Scientific EffectStress distribution:

Implementation Method 2

The flexible lattice body includes a flex beam member coupling the input body to the output body... while transferring torque

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS10280985B2Flexible couplings for power transmissions

Publication Date: 2019.05.07 GOODRICH CORP

AI summary

A flexible coupling includes an input body, an output body offset from the input body, and a flexible lattice body. The flexible lattice body includes a flex beam member coupling the input body to the output body. The flex beam member has a rounded cross-sectional area with a centrally disposed minimum cross-sectional area to reduce peak stress in the flex beam member while transferring torque and accommodating misalignment between the input body and the output body. The flexible coupling is jointless, simplifying fabrication, and has a free-form geometry, reducing weight.