Rivet Nut Thread Ridge Recesses for Lubricity Retention
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Solution Overview
Problem
Conventional rivet nuts experience excessive friction during attachment due to the dissipation of lubricating oil during transportation and storage, leading to inadequate lubricity and poor fastening performance.
Innovation Solution
The rivet nut features recesses at the top of the thread ridge with a narrow-mouth shape to retain lubricating oil, reducing friction and maintaining lubricity over time, and is manufactured using a rolled tapping process to form the thread ridge with a higher hardness than the cylindrical body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional rivet nut is manufactured by cutting process, then the manufacturing cost is reduced, but the lubricity deteriorates due to excessive friction during attachment
Solution Approach 1:
The patent applies preliminary action by forming recesses at the top of the thread ridge before the rivet nut is put into service. These recesses are pre-formed during manufacturing to retain lubricating oil, ensuring that lubrication is available when needed during attachment operations, thus preventing excessive friction and maintaining reliable lubricity throughout storage and usage.
2Reliability
If lubricating oil is applied to the thread ridge, then the lubricity is improved, but the lubricating oil dissipates during transportation and storage
Solution Approach 1:
The patent applies local quality by creating recesses specifically at the top of the thread ridge where lubrication is most needed. This localized structural modification allows the lubricating oil to be retained at the critical friction interface, ensuring that lubrication is concentrated where it is most effective while preventing dissipation during transportation and storage.
Solution Approach 2:
The recesses are pre-formed during manufacturing to prepare the thread ridge for optimal lubrication. This preliminary structural preparation ensures that when lubricating oil is applied, it is immediately retained in the recesses rather than dissipating, thus maintaining reliable lubricity throughout the product lifecycle.
3Strength
If the thread ridge is formed with rolled tapping process, then the hardness is increased, but the manufacturing complexity increases
Solution Approach 1:
The patent merges two manufacturing operations into one: the rolled tapping process that forms the thread ridge and the simultaneous formation of recesses at the top of the thread ridge. This combined process achieves both the desired high hardness of the thread ridge and the lubrication-retaining recesses in a single manufacturing step, thereby increasing strength without proportionally increasing manufacturing complexity.
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 design ensures smoother attachment and assembly by minimizing friction between the thread ridge and external thread portions, while maintaining excellent lubricity and strength, even after storage and transportation.
Implementation Method 1
recesses which have a narrowed opening and in which a lubricating oil is retained
Implementation Method 2
manufactured by a rolled tapping process to form the thread ridge with a higher hardness than the cylindrical body
Data Source
Figure 1A
Figure 1B
Figure 1C~2
AI summary
An object of the disclosure is to provide a rivet nut capable of sufficiently preventing lowering of a lubricity even after transportation and/or storage, and a method for manufacturing the rivet nut. The disclosure provides a rivet nut 100 including: a cylindrical portion 10 including a cylindrical body 1 opening in an axial direction, and a thread ridge 2 provided in an inner circumferential surface of the cylindrical body; and a flange portion 30 provided at one end of the cylindrical body 1, wherein a recess 20 is provided at a top of the thread ridge 2. The disclosure further provides a method for manufacturing a rivet nut, the method comprising performing a rolled tapping process to form a thread ridge 2 while forming a recess 20 at a top of the thread ridge 2.