Tiltrotor Gearbox Fitting With Downstop Striker for Load Absorption
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Solution Overview
Problem
Designing tiltrotor aircraft propulsion systems that balance performance considerations such as size, weight, power efficiency, and structural loads while allowing for smooth transitions between helicopter and airplane modes is challenging, particularly in supporting conversion actuator and downstop striker configurations.
Innovation Solution
A fitting system is introduced that includes a proprotor gearbox, a conversion actuator, and a downstop striker, where the downstop striker is mounted between the proprotor gearbox and the conversion actuator, allowing for alignment and movement between airplane and helicopter modes, with a varying width design to absorb loads and reduce part count and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a downstop striker is mounted between the proprotor gearbox and the conversion actuator, then structural support and load absorption are improved, but device complexity increases
Solution Approach 1:
The downstop striker is integrated into the fitting structure, combining the downstop function with the fitting that already connects the conversion actuator to the proprotor gearbox. This integration provides structural support and load absorption while avoiding the need for a completely separate downstop component, thus reducing overall device complexity.
Solution Approach 2:
The fitting structure serves multiple functions: it acts as both the connection element between the conversion actuator and proprotor gearbox, and simultaneously houses the downstop striker that provides structural support and load absorption. This multi-functionality improves strength without proportionally increasing device complexity.
2Weight of moving object
If a varying width design is used for the downstop striker, then weight and part count are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The downstop striker features a varying width design where the cross-sectional dimensions change along its length. This local variation in geometry allows the striker to optimize material distribution - thicker sections where strength is needed and thinner sections where weight reduction is prioritized. The design reduces overall weight while maintaining necessary structural properties through localized quality adjustments.
3Reliability
If the downstop striker is aligned to be in contact when the proprotor gearbox is positioned in an airplane mode, then reliability is improved, but ease of operation decreases
Solution Approach 1:
The downstop striker is designed to dynamically engage with the downstop surface only when needed - specifically when the proprotor gearbox reaches the airplane mode position. During normal operation and transitions, the striker remains disengaged, allowing free movement. This dynamic engagement mechanism ensures reliability by providing support when required while maintaining ease of operation during mode transitions.
Data Source
AI summary
A wing is provided in one example embodiment and may include an outboard rib; a proprotor gearbox, wherein the proprotor gearbox is located inboard of the outboard rib; a fitting attached to the proprotor gearbox; and a conversion actuator, wherein the conversion actuator is attached to the wing and is mechanically coupled to the fitting. The wing may further include a downstop striker in which the downstop striker may be mounted to the fitting and the downstop striker may be between the proprotor gearbox and the conversion actuator. The wing may further include a downstop mounted on a top side of the outboard rib, wherein the downstop and the downstop striker are aligned to be in contact when the proprotor gearbox is positioned in an airplane mode.