Segmented Nut Retention via Asymmetric Interface
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Solution Overview
Problem
Existing segmented nuts face challenges with unpredictable and variable release torque due to galling issues and tight tolerancing requirements, which complicates mass production and storage stability.
Innovation Solution
The design incorporates a segmented nut with a sleeve and inner segments featuring distinct interface portions that allow radial movement and axial retention, reducing the need for high tolerance machining and minimizing galling, while providing consistent release torque through a self-centering mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an interference fit is used between the inner segments and outer sleeve to prevent separation during transport and storage, then the stability of the assembled nut is improved, but the release torque becomes sensitive to tolerance variations and production difficulty increases
Solution Approach 1:
The interface between the sleeve and segments is segmented into multiple discrete engagement points (protrusions and recesses) around the circumference, allowing the segments to be retained stably during transport while providing defined release paths that reduce sensitivity to overall interference fit tolerances
Solution Approach 2:
The interface design provides different local characteristics: strong engagement at the protrusion-recess interfaces for transport stability, while maintaining clearance or reduced engagement zones that facilitate controlled release without requiring tight tolerance control across the entire interface
2Strength
If an interference fit is used between the inner segments and outer sleeve, then the engagement strength is improved, but galling issues occur during press-fitting
Solution Approach 1:
The press-fit interface is segmented into discrete localized contact zones rather than a continuous interference fit, concentrating the engagement strength at specific protrusion-recess interfaces while reducing overall contact area that could generate galling
Solution Approach 2:
The interface design creates localized high-strength engagement zones at the protrusion-recess interfaces while maintaining lower contact pressure or clearance in adjacent areas, preventing the widespread galling that occurs with uniform interference fits
3Force
If radiused contact surfaces are used between the sleeve and segments, then the radial constraint is sufficient, but accurate tolerancing is required to prevent accidental disassembly
Solution Approach 1:
The interface features asymmetric protrusions and recesses that provide stable retention in the assembled state while creating a defined release mechanism, eliminating the need for tight tolerances to prevent accidental disassembly that would be required with symmetric radiused surfaces
Data Source
Figure 1~4
Figure 5~10b
Figure 11a~14
AI summary
A segmented nut has inner segments and an outer sleeve. Part of the sleeve interface portion and part of the segment interface portion engage when the sleeve rotates relative to the inner nut during release of the segmented nut with part of the segment interface portion at a greater distance from a central axis of the segmented nut than a minimum distance of the at least part of the sleeve interface portion from the central axis. One or more of the segments can include a retainer preventing the sleeve moving toward a free face of the segment(s). One or more of the segments can have a flange portion providing an increased working (compression) face relative to a plain segmented nut. An assembled segmented nut can include some radial freeplay for the segments to move radially whilst being retained within the sleeve prior to application of the segmented nut to a threaded bolt, stud or rod such that threading of the segmented nut onto the thread of the bolt, stud or rod removes the freeplay.