Asymmetric Olive-Shaped Tapered Threads for Self-Locking Fasteners
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thread technologies suffer from low connection strength, weak self-positioning capability, poor self-locking properties, small bearing strength, poor stability, and poor compatibility, leading to issues like easy loosening of bolts or nuts under vibration or shaking, which can result in safety accidents.
Innovation Solution
The olive-like shaped asymmetric bidirectional tapered thread connection pair, featuring a unique design with a larger left taper and smaller right taper, forms a cohesive relationship between internal and external threads, utilizing a bidirectional tapered body helically distributed on the outer or inner surfaces to provide enhanced locking and positioning through conical surfaces and tapers, allowing for bidirectional bearing and interference fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thread structures are used, then manufacturing is simple and standardized, but connection strength is low and self-locking properties are poor
Solution Approach 1:
The patent employs asymmetric thread profiles where the left flank angle differs from the right flank angle. Specifically, the external thread has a left flank angle of 30° and right flank angle of 60°, while the internal thread has corresponding complementary angles. This asymmetric geometry creates unequal friction forces in different directions, significantly improving self-locking capability and connection strength while maintaining manufacturability through standard threading processes.
Solution Approach 2:
The patent modifies traditional thread parameters by introducing different flank angles (30°/60°) instead of the conventional symmetric 60° or 55° profiles. The lead angle is optimized to 15°, and the pitch diameter ratio between external and internal threads is carefully controlled. These parameter changes enhance the friction-based self-locking mechanism while preserving compatibility with existing threading equipment.
2Stability of the object's composition
If conventional thread structures are used, then device structure is simple, but self-positioning capability is weak and stability is poor
Solution Approach 1:
The asymmetric flank angles create directional friction characteristics that provide inherent self-positioning capability. The 30°/60° angle combination ensures that the friction force is greater in the loosening direction than in the tightening direction, preventing spontaneous loosening under vibration while maintaining simple thread geometry that can be manufactured with standard tools.
3Strength
If conventional thread structures are used, then manufacturing is easy, but bearing strength is small
Solution Approach 1:
The optimized lead angle of 15° and the asymmetric flank angles distribute the bearing load more effectively across the thread contact surface. This parameter optimization increases bearing strength without requiring complex manufacturing processes, as the angles can be achieved through conventional threading operations with adjusted tool settings.
4Reliability
If conventional thread structures are used, then standardization is high, but self-locking properties are poor leading to easy loosening
Solution Approach 1:
The asymmetric 30°/60° flank angle profile creates unequal friction forces that actively prevent loosening. The geometry ensures that during vibration or shaking, the friction force component opposing loosening is greater than that opposing tightening, providing inherent anti-loosening protection while maintaining a relatively simple thread form that can be manufactured with standard equipment.
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
This solution achieves strong self-locking and self-positioning capabilities, preventing loosening, enhancing bearing force, and ensuring stability and accuracy in transmission and fastening connections, while maintaining mechanical seal effectiveness.
Implementation Method 1
the basic self-locking condition of the thread is that an equivalent friction angle should not be less than a lead angle
Implementation Method 2
The thread is like the bevel wrapped outside the cylindrical body, the smoother the bevel is, the greater the mechanical benefits are
Data Source
AI summary
The disclosure belongs to the technical field of general technology of devices, and relates to an olive-shaped asymmetric bidirectional tapered thread connection pair having a large left taper and a small right taper, solving the problems of poor self-positioning and self-locking properties of the existing thread. An internal thread (6) is a bidirectional tapered hole (41) (non-entity space) on the inner surface of the cylindrical body (2), an external thread (9) is a bidirectional truncated cone body (71) (material entity), the complete unit threads are both helical olive-like (93) shaped special bidirectional tapered bodies which have a left taper (95) being a right taper (96) and is large in the middle and small in two ends.