Spline Torque Tube Coupling for Aircraft Wing Flex Alignment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing torque tube assemblies for aircraft high lift devices face issues with large rotational envelopes, bolt loosening, and structural integrity due to wing flexing, which affects torque transmission and alignment.

Innovation Solution

The use of spline couplings with integral yokes and retainer mechanisms that allow axial movement and angular adjustment, eliminating the need for bolted flanges, thereby reducing the rotational envelope and enhancing structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If bolted flanges are used to couple torque tube to pinion gear, then structural integrity is improved, but rotational envelope becomes large requiring more space

Engineering Contradiction:

Improvestructural integrityVSAvoidrotational envelope

Core Design Contradiction:

StrengthVSArea of stationary object

Solution Approach 1:

The patent removes the flange component entirely from the torque tube assembly, replacing it with a spline coupling that integrates the coupling function directly into the torque tube structure. This extraction of the flange eliminates the large rotational envelope while maintaining structural integrity through the spline engagement mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the flange and coupling functions into a single integrated spline coupling structure. The spline coupling combines torque transmission, alignment, and retention functions that were previously separated across multiple components (flange, bolts, coupling), thereby reducing the rotational envelope while preserving structural integrity.

Inventive Principle:

Principle #5Merging (Combining)

2Power

If bolted flanges are used to couple torque tube to pinion gear, then torque transmission is achieved, but bolts can loosen reducing structural integrity

Engineering Contradiction:

Improvetorque transmissionVSAvoidstructural integrity

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent replaces the bolted mechanical connection system with a spline engagement system. The spline coupling uses precise geometric interlocking between splines on the torque tube and corresponding splines in the pinion gear, eliminating bolts entirely. This substitution provides positive mechanical engagement that transmits torque reliably without the risk of loosening.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of using bolts to pull components together (tensile force), the spline coupling uses compressive and shear forces through direct geometric interlocking. The splines engage in a way that creates mechanical interference, preventing relative motion and torque loss without relying on friction or bolt preload.

Inventive Principle:

Principle #13The other way round (Inversion)

3Power

If rigid coupling is used between torque tube and drive shaft, then torque transmission is efficient, but wing flexing causes additional forces and strain

Engineering Contradiction:

Improvetorque transmission efficiencyVSAvoidstrain on torque tube

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The patent introduces dynamic flexibility through the spline coupling mechanism, which allows for minor angular and axial movements while maintaining torque transmission. The spline engagement can accommodate small misalignments and flexing motions that occur during wing deformation, absorbing these dynamic loads without creating excessive forces on the torque tube.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The spline coupling changes the mechanical parameters of the connection by allowing controlled play and movement ranges. The engagement geometry permits small variations in position and orientation, transforming the rigid connection into a semi-flexible one that adapts to wing flexing while maintaining efficient torque transmission through the spline teeth.

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If spline coupling allows axial movement and angular adjustment, then adaptability to wing flexing is improved, but device complexity increases

Engineering Contradiction:

Improveadjustment capabilityVSAvoidcoupling mechanism complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spline coupling performs multiple functions simultaneously: torque transmission, axial movement accommodation, angular adjustment, and retention. By integrating these functions into a single coupling mechanism rather than using separate components for each function, the patent achieves high adaptability while actually reducing overall system complexity compared to multi-component solutions.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP3514054B1Apparatus and methods for rigging a torque tube assembly in an aircraft

Publication Date: 2022.08.10 THE BOEING CO

Figure 1
Figure 2
Figure 3~4

AI summary

Example apparatus and methods for rigging a torque tube assembly (200) for actuating high-lift devices in an aircraft are described herein. An example torque tube assembly (200) includes a torque tube (304) and a spline coupling (404) coupled to an end (302) of the torque tube (304). The spline coupling (404) has an opening (410) to receive a spline gear (1400) on a drive shaft (228) of an aircraft high lift device actuator. The torque tube assembly also includes a retainer (1302) coupled to the spline coupling (404). The retainer (1302) blocks at least a portion of the opening (410) in the spline coupling (404) to prevent the spline coupling from being moved off of the spline gear (1400) on the drive shaft (228).