Dual-Thread Nut Fastening Structure Preventing Loosening
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Solution Overview
Problem
Existing part-fastening structures for rotary shafts face issues with nut loosening and increased axial dimensions due to insufficient frictional force, leading to potential slippage and dimensional issues.
Innovation Solution
A part-fastening structure utilizing a combination of right-hand and left-hand threads for the first and second nut members, connected by a connecting member to prevent relative rotation, along with groove and projecting portions for secure engagement, ensuring both nuts remain fastened without additional parts and minimizing axial dimension increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second nut is added to prevent loosening, then reliability of fastening is improved, but the axial dimension of the rotary shaft increases
Solution Approach 1:
The patent combines the loosening prevention function into the existing nut structure by adding a groove portion and projecting portion mechanism to the second nut, eliminating the need for a separate third nut. This merging approach maintains fastening reliability while avoiding the axial dimension increase that would result from adding another nut component.
Solution Approach 2:
The second nut structure incorporates self-locking features through the groove portion and projecting portion that automatically engage to prevent loosening. This self-service mechanism eliminates the need for additional nuts or complex external locking devices, thereby preventing axial dimension increase while maintaining fastening reliability.
2Stability of the object's composition
If sufficient frictional force is provided to prevent nut slippage, then fastening stability is improved, but the axial dimension increases due to requiring additional nuts
Solution Approach 1:
The patent merges the anti-loosening and anti-slippage functions into the second nut structure itself through the groove portion and projecting portion mechanism. This integration provides sufficient frictional force and stability without requiring additional nuts that would increase the axial dimension.
Solution Approach 2:
The groove portion and projecting portion act as an intermediary mechanism between the second nut and the first nut, providing the necessary frictional force and mechanical interlocking to prevent slippage and loosening without requiring additional nuts or increasing axial dimension.
3Reliability
If multiple nuts are used to prevent loosening, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple fastening functions (primary fastening, loosening prevention, and anti-slippage) into a integrated second nut structure with groove portion and projecting portion. This merging reduces the total number of components from three nuts to two nuts, thereby reducing device complexity while maintaining fastening reliability.
Solution Approach 2:
The second nut is designed with multi-functionality, serving both as the primary fastening element and incorporating the groove portion and projecting portion for loosening prevention. This universal design eliminates the need for separate dedicated locking nuts, reducing overall structure complexity while maintaining reliability.
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 effectively prevents nut loosening, reduces the number of parts required, and minimizes axial dimension increase by ensuring secure fastening through the opposing thread directions and simple engagement mechanisms, maintaining stability even under varying operational conditions.
Implementation Method 1
sufficiently large frictional force are acting on contact portions of the respectively first and second nuts; and the two nuts accordingly do not turn relative to each other
Data Source
AI summary
In a part-fastening structure, one of respective threads of a first nut member for fastening a first part and a second nut member for fastening a second part, is a right-hand thread, and the other is a left-hand thread. The members are connected together by a connecting member against relative rotation. Thus, rotation of the first member in its loosening direction acts in a direction of fastening the second member via the connecting member, and rotation of the second member in its loosening direction acts in a direction of fastening the first member via the connecting member, so that looseness of both the members is prevented, while reducing the number of locking parts to minimize an increase in an axial dimension.