Curved Thread Bolt Geometry for Vibration-Resistant Fastening
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Solution Overview
Problem
Bolts experience self-loosening and thread breakage due to vibration and dynamic loads, which existing solutions like washers or surface roughening fail to adequately address, leading to premature failure of bolted joints.
Innovation Solution
A bolt design featuring a thread portion with a continuous curved bearing surface including concave and convex surfaces, allowing for increased elastic deformation and stress distribution, thereby enhancing frictional force and preventing self-loosening and breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a washer or friction layer is added between contact surfaces, then self-loosening is prevented, but device complexity and manufacturing cost increase
Solution Approach 1:
The bearing surface of the thread portion is designed as a continuous curved surface with specific concave and convex sections, replacing the conventional flat or simple angled bearing surface. This curved geometry enables the thread to undergo larger elastic deformation under preload, storing elastic potential energy that generates axial restoring force to prevent self-loosening during vibration, without requiring additional components like washers or friction layers
Solution Approach 2:
The invention changes the geometric parameters of the thread bearing surface by introducing a continuous curved profile with controlled concave and convex sections. This parameter modification allows the thread to achieve optimal elastic deformation characteristics, enhancing the storage of elastic potential energy and the subsequent generation of axial force to counteract loosening tendencies under dynamic loading conditions
2Ease of manufacture
If thread corners are sharp, then manufacturing is easier, but stress concentration increases leading to thread breakage
Solution Approach 1:
The continuous curved bearing surface inherently provides rounded transitions instead of sharp corners at the thread roots and crests. This curved geometry distributes stress more uniformly throughout the thread structure, eliminating stress concentration points that would initiate cracks under cyclic loading, while remaining compatible with standard manufacturing processes
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 bolt design effectively prevents self-loosening and thread breakage by increasing frictional force and evenly distributing stress, ensuring reliable joint integrity under vibration and impact.
Implementation Method 1
the thread portion would be able to have a larger range of elastic deformation during preload, the elastically deformed thread portion can store a larger amount of elastic potential energy against the fastener engaged with such bolt and thus increasing the frictional force
Implementation Method 2
the bearing surface of such bolt is also able to evenly distribute the stress while an axial load is applied on the thread portion so that the bolt of the disclosure has a greater capability in preventing the thread from breaking due to vibration or sudden impact
Data Source
AI summary
The disclosure provides a bolt including a main body, a head portion and a thread portion. The main body has a central axis. The head portion connects the main body. The thread portion is connected to the main body and runs around the central axis. The thread portion has a bearing surface facing toward the head portion. The bearing surface is a continuous curved surface or has an inflection point. The bearing surface includes a concave curved surface, a convex curved surface and a flank surface. The concave curved surface connects the main body. The convex curved surface is located further away from the main body than the concave curved surface. One side of the convex curved surface connects the concave curved surface, and another side of the convex curved surface connects the flank surface.