Composite Driveshaft Virtual Hinge Axial Compensation

Solution Overview

Problem

Traditional driveshafts in rotary wing aircraft, especially in high-speed and high-torque applications, are heavier due to the use of traditional misalignment compensating devices like U-joints, which are undesirable in weight-sensitive aerospace applications.

Innovation Solution

A composite driveshaft with integrated axial misalignment compensating features made from lightweight materials, incorporating a virtual hinge design that accommodates axial changes without material failure, reducing weight and mechanical complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional U-joints or misalignment compensating devices are used in driveshafts, then axial misalignment is compensated and torque transmission is ensured, but weight increases and mechanical complexity increases

Engineering Contradiction:

Improveaxial misalignment compensationVSAvoiddriveshaft weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent integrates the misalignment compensation function directly into the driveshaft body by creating a virtual hinge through strategic material removal and geometric modification of the composite structure. This merges the previously separate components (driveshaft + U-joint) into a single integrated unit, eliminating the need for additional misalignment compensating devices while maintaining the weight reduction benefits of composite materials

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces traditional mechanical U-joints with a virtual hinge concept implemented through composite material geometry. The virtual hinge uses the inherent flexibility and anisotropic properties of composite laminates to accommodate axial misalignment through controlled deformation patterns, substituting a complex mechanical joint with a streamlined composite structural feature

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional U-joints are used in driveshafts, then misalignment is compensated, but device complexity increases

Engineering Contradiction:

Improvemisalignment compensationVSAvoidmechanical complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the misalignment compensation function directly into the driveshaft body by creating a virtual hinge through strategic material removal and geometric modification of the composite structure. This merges the previously separate components (driveshaft + U-joint) into a single integrated unit, eliminating the need for additional misalignment compensating devices while maintaining the weight reduction benefits of composite materials

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the essential misalignment compensation function from the traditional U-joint mechanism and implements it directly within the driveshaft's composite structure. By removing unnecessary mechanical components and retaining only the critical functional capability through geometric modification of the composite layup, the design simplifies the overall system while preserving misalignment accommodation

Inventive Principle:

Principle #2Taking out (Extraction)

3Weight of moving object

If composite materials are used to reduce weight, then weight decreases, but the structure must accommodate axial changes without material failure

Engineering Contradiction:

Improvedriveshaft weightVSAvoidmaterial failure resistance

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating regions of modified stiffness and flexibility within the composite driveshaft structure. The virtual hinge incorporates localized variations in laminate orientation, material stacking sequence, and geometric configuration that enable controlled deformation in specific areas while maintaining structural integrity and load-bearing capacity in other regions, allowing the lightweight composite structure to accommodate axial changes without failure

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9909624B2Composite driveshaft for a rotary system

Publication Date: 2018.03.06 ROHR INC

AI summary

A composite driveshaft includes a body having a first end, a second end, and an intermediate portion defining a driveshaft axis (DSA). The first end defines a first coupling region and the second end defines a second coupling region. At least one of the first and second coupling regions defines a virtual hinge configured to accommodate both bending moments and axial changes of the body.