Rotary Actuator Sleeve Locking for Lightweight Wing Attachment
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Solution Overview
Problem
The existing rotary actuator mounting systems for aircraft wing assemblies are bulky, heavy, and labor-intensive to assemble, with a high risk of human error and localized stress-induced loosening or damage during flight, due to the use of multiple lugs and bolts for attachment.
Innovation Solution
The use of radially extending splines on circumferential earth and output members of the rotary actuator that engage with complementary splines in a mounting sleeve for secure attachment, reducing the need for traditional lugs and bolts, thereby minimizing size, weight, and assembly time while ensuring secure locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lugs and bolts are used to attach earth members to the wing structure, then secure attachment is achieved, but the overall size and weight of the actuator assembly increases
Solution Approach 1:
The mounting sleeve integrates multiple attachment functions into a single component. The sleeve receives and secures multiple earth members simultaneously through internal splines, eliminating the need for separate lugs and multiple bolts. This merging of attachment functions reduces the overall number of parts and decreases the weight of the actuator assembly while maintaining secure attachment to the wing structure.
Solution Approach 2:
The mounting sleeve serves multiple functions: it provides structural support for attaching earth members to the wing, enables precise positioning through splined engagement, and distributes mechanical loads across multiple attachment points. This multi-functionality replaces what would traditionally require separate components, reducing overall assembly weight while ensuring reliable attachment.
2Reliability
If multiple lugs and bolts are used for attachment, then secure fixation is achieved, but the assembly time and labour intensity increases
Solution Approach 1:
The mounting sleeve combines multiple attachment operations into a single assembly action. Multiple earth members with splines engage with the sleeve's internal splines simultaneously, allowing all attachments to be secured in one operation rather than requiring sequential fastening of multiple lugs and bolts. This dramatically reduces assembly time and labour intensity while maintaining secure fixation.
Solution Approach 2:
The splined engagement mechanism between the earth members and mounting sleeve provides self-aligning and self-securing functionality. The complementary splines automatically guide the earth members into proper position and lock them in place through mechanical engagement, eliminating the need for manual alignment and repetitive fastening operations that characterize traditional lug-and-bolt assembly.
3Reliability
If traditional lug and bolt attachment is used, then attachment is achieved, but local stresses can loosen or damage the fastening during flight
Solution Approach 1:
The mounting sleeve distributes attachment loads across multiple segmented engagement points along its length. The internal splines create multiple contact surfaces that share the mechanical loads from flight operations, preventing concentration of stress at single fastening points. This segmentation of load paths enhances fastening durability by reducing localized stresses that could loosen or damage traditional bolted connections.
Solution Approach 2:
The splined engagement between the mounting sleeve and earth members provides a dynamic load-distributing mechanism. The multiple spline teeth engage progressively and share loads dynamically during flight maneuvers, allowing the attachment system to adapt to varying stress conditions. This dynamic load distribution prevents the static stress concentrations that lead to fastening failure in traditional rigid lug-and-bolt configurations.
Data Source
Figure 1
Figure 2
AI summary
A rotary actuator assembly for moving a first relatively movable part (1) relative to a second relatively movable part (2), the assembly comprising a rotary actuator (100) having a plurality of circumferential earth members (1120) for attachment to one of the first and the second relatively movable parts and a plurality of circumferential output members (1140) for attachment to the other of the first and second relatively movable parts, and wherein at least the plurality of circumferential earth members or the plurality of circumferential output members is provided with radially outwardly extending locking features (1121, 1141) around their circumference configured to be received in a mounting sleeve having complementary locking features to engage with the radially outwardly extending locking features.