Wing Tip Actuator Clutch With Frusto-Conical Torque Transfer
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Solution Overview
Problem
Aircraft wing tip devices require a clutch system that can transmit high torque while being compact and durable, as existing solutions often fail under significant loads and have spatial constraints within aircraft.
Innovation Solution
A clutch system utilizing a coaxial stack of frusto-conical friction surfaces with spacer means to separate the surfaces in the disengaged state, allowing for high torque transmission within a small diameter and reducing wear, featuring a combination of friction and dog clutches for enhanced reliability and space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a sufficiently powerful clutch device is used to withstand significant torques, then torque transmission capability is improved, but device size increases and spatial constraints are violated
Solution Approach 1:
The clutch device employs a nested arrangement where friction members are stacked coaxially one inside another, similar to nested dolls. Each friction member contains internal friction surfaces that engage with corresponding surfaces on adjacent members, allowing multiple friction interfaces to be contained within a compact cylindrical volume. This nesting approach maximizes torque transmission capability within limited spatial constraints by utilizing the internal volume of each friction member.
Solution Approach 2:
The invention transitions from conventional single-plane friction surfaces to three-dimensional frusto-conical friction surfaces arranged coaxially. By utilizing the conical geometry and stacking multiple members along the axial dimension, the design achieves high torque capacity in a compact radial envelope. The frusto-conical surfaces provide progressive engagement and distribute contact stresses across multiple dimensions, enabling powerful torque transmission within a small overall diameter.
2Volume of moving object
If friction surfaces are kept close together to reduce size, then spatial efficiency is improved, but wear between surfaces increases
Solution Approach 1:
The clutch device is segmented into multiple independent friction members, each containing its own friction surfaces. This segmentation allows the wear to be distributed across multiple discrete contact interfaces rather than concentrated in a single interface. The spacer means further segments the arrangement by maintaining controlled gaps between certain friction members, preventing excessive wear while maintaining compact overall dimensions.
Solution Approach 2:
Spacer means are introduced as intermediary elements between certain friction members. These spacers maintain controlled gaps that prevent direct contact and excessive wear during normal operation, while still allowing the friction members to be positioned close together for compactness. The spacers act as mediators that manage the interaction between friction surfaces, enabling the system to achieve both small size and long lifespan by controlling when and how friction surfaces engage.
3Reliability
If a clutch device is designed to withstand high torques, then reliability is improved, but device complexity increases
Solution Approach 1:
The invention merges multiple friction members with frusto-conical surfaces into a single integrated clutch assembly. By combining multiple friction interfaces within one compact structure and using common mounting features, the design achieves high reliability through distributed load-bearing capacity without proportionally increasing complexity. The coaxial arrangement and standardized friction member geometry allow for modular assembly, maintaining relative simplicity while withstanding high torques.
Solution Approach 2:
The use of frusto-conical (curved) friction surfaces instead of flat surfaces provides inherent mechanical advantages. The conical geometry creates progressive contact and distributes stresses more evenly across the friction interfaces, improving durability under high torque loads. The curved surfaces also facilitate smoother engagement and disengagement, reducing shock loads and simplifying the control mechanism compared to rigid flat-surface clutches.
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 provides a scalable, long-lasting clutch system capable of transmitting high torque efficiently, reducing wear and maintaining structural integrity within spatial constraints, thus protecting the wing tip actuator from back-driving and ensuring reliable operation.
Implementation Method 1
The clutch is operable to selectively transmit torque between the wing tip actuator and the wing tip device via engagement of a first shaft with a second shaft. The clutch comprises first and second friction members coupled with the first shaft. The first and second friction members each have a frusto-conical friction surface. The clutch also comprises a third friction member coupled with the second shaft. The third friction member is arranged coaxially with, and between, the first and second friction members.
Data Source
AI summary
A clutch for use in actuating an aircraft wing tip device is disclosed. The clutch includes first and second friction members each having a frusto-conical friction surface, and a third friction member arranged coaxially with, and between, the first and second friction members. The third friction member has first and second frusto-conical friction surfaces. When the clutch is engaged, the first and second friction surfaces of the third friction member are brought into contact with the friction surfaces of the first and second friction members, respectively. The clutch also includes spacer means operable to separate the friction surfaces from one another when the clutch is in a disengaged state.