Thread-Forming Nut with Segmented Threads for Coated Bolts
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Solution Overview
Problem
Existing nuts struggle to form functional threads on coated bolts or those with blocked threads, requiring costly re-threading or high torque, which can lead to seizing issues.
Innovation Solution
A thread-forming nut with a core hole featuring load-bearing threads arranged peripherally, including fully formed and incomplete sections with clearances, allowing for thread formation on coated or blocked bolts without re-threading, and providing a self-locking mechanism to prevent loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional nut is used on a coated bolt, then the coating provides corrosion protection, but the coating blocks the thread formation and causes seizing or high torque
Solution Approach 1:
The thread is segmented into fully formed sections and incomplete sections with clearances. This segmentation allows the nut to engage with the bolt in a way that accommodates coating deposits, enabling thread formation without complete blocking while maintaining corrosion protection.
Solution Approach 2:
Different sections of the thread have different qualities: fully formed sections provide structural integrity and load bearing, while incomplete sections with clearances provide space for coating deposits and facilitate thread formation. This local differentiation resolves the contradiction between corrosion protection and thread formation ease.
2Ease of manufacture
If high torque is applied to screw a nut onto a coated bolt, then thread formation is achieved, but seizing occurs or uncontrolled high torque results
Solution Approach 1:
By segmenting the thread into fully formed and incomplete sections, the nut can engage with the coated bolt progressively. The incomplete sections with clearances reduce resistance during engagement, preventing sudden high torque peaks and seizing while still achieving proper thread formation.
Solution Approach 2:
The incomplete thread sections provide partial engagement that accommodates coating deposits. This partial action allows the nut to thread onto the bolt without requiring excessive force, thereby preventing seizing while still achieving functional thread formation in the fully formed sections.
3Strength
If the thread is completely formed, then load bearing capacity is maximized, but coating deposits block thread formation and require re-threading
Solution Approach 1:
The thread is divided into fully formed load-bearing sections and incomplete sections with clearances. This segmentation allows the nut to accommodate coating deposits in the incomplete sections while maintaining full load-bearing capacity in the fully formed sections, eliminating the need for re-threading and improving productivity.
Solution Approach 2:
The coating deposits that would normally block thread formation are accommodated in the incomplete thread sections with clearances. This converts the harmful effect of coating deposits into a beneficial design feature that simplifies the threading process and eliminates re-threading operations while maintaining full load-bearing capacity.
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
Enables efficient thread formation on a variety of materials without chip removal, reduces costs by avoiding re-threading, and enhances the self-locking effect to prevent connection loosening due to vibrations.
Implementation Method 1
If the counterpart, for example the nut, already has a thread, this is further machined by the self-tapping thread of the bolt. In the case of a self-tapping thread, for example in the form of a trilobular thread, this forms the existing thread of the counterpart further, or only deforms it elastically.
Data Source
Figure 1~3
Figure 4A~4
Figure 5
AI summary
A thread-producing nut (13) for a screwed connection, wherein a core hole (3) which is provided with thread turns is designed for positively locking, frictionally locking and releasable connection to an, in particular, cylindrical bolt or pin, in such a way that the thread turns have completely formed thread turns in certain sections when viewed in the circumferential direction and that free spaces (10, 11, 12) with thread turns which are formed incompletely in terms of their height are provided between the completely formed sections of the thread turns. Furthermore, a blank for manufacturing the nut and a screwed connection composed of such a nut and a bolt are the subject matter of the invention.