Segmented Nut Thread Structure for Anti-Loosening Load Distribution
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Solution Overview
Problem
Existing nut designs face issues with excessive load distribution on the first thread portion leading to fracture and deformation in vibration environments, reducing fastening axial force.
Innovation Solution
A screw structure with a female thread featuring a first and second threaded region, where the pressure and clearance flanks of the female thread are designed to contact the male thread flanks, with the second region having convex arcuate shapes to generate prevailing torque and reduce load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the first thread portion of the female thread bears the largest proportion of distributed load, then the fastening axial force is effectively transmitted, but the first thread portion fractures first under excessive axial force or deformation in vibration environments
Solution Approach 1:
The female thread is divided into a first threaded region and a second threaded region with different structural characteristics. The first region has flat flanks for basic engagement, while the second region has convex arcuate flanks for load distribution and anti-loosening, segmenting the load-bearing function across different zones
Solution Approach 2:
Different regions of the female thread are given different local qualities: the first threaded region has flat pressure and clearance flanks for standard engagement, while the second threaded region has convex arcuate flanks specifically designed to generate prevailing torque and distribute load, making each region optimized for its specific function
2Reliability
If convex arcuate surfaces are formed on the female thread flank surfaces, then play between male and female threads is eliminated and anti-loosening effect is achieved, but the structure complexity increases
Solution Approach 1:
The anti-loosening function is segmented to only the second threaded region, while the first threaded region maintains a simple flat-flank structure for basic engagement. This segmentation applies the complex convex arcuate profile only where needed for anti-loosening, reducing overall structural complexity while maintaining reliability
Solution Approach 2:
The convex arcuate profile is applied locally only to the second threaded region rather than the entire female thread. This local application provides the anti-loosening effect where most needed (in the engaged portion) while keeping the majority of the thread structure simple and easy to manufacture
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 screw structure reduces stress concentration on the first thread portion, prevents seizure, and maintains effective fastening even in vibration environments by generating substantial prevailing torque.
Implementation Method 1
the pressure flanks of the female and male threads contact each other, but the clearance flanks also contact each other, generating prevailing torque during nut tightening operations, which provides an anti-loosening effect
Data Source
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AI summary
A screw structure capable of reducing the proportion of distributed load of fastening axial force applied to the first thread crest while generating an anti-loosening effect through prevailing torque. In a screw structure comprising a bolt (1) and a nut (2), the female thread (20) of the nut (2) has a first threaded region (21) and a second threaded region (22) with convex arcuate flank surfaces (22a, 22b). When the female thread (20) engages with the male thread (10) of the bolt (1), in the first threaded region (21), the pressure flank (21a) contacts the male thread (10) while maintaining a gap between the clearance flanks (21b, 10b). In the second threaded region (22), both the pressure and clearance flanks (22a, 22b) of the female thread (20) contact the pressure and clearance flanks (10a, 10b) of the male thread (10), respectively.