Guide Bolt Structure for Seizure-Free Threaded Fastening
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Solution Overview
Problem
Existing bolts fail to effectively suppress seizure due to both oblique insertion and biting of foreign substances, such as spatters and coated thick films, during fastening operations.
Innovation Solution
A bolt design featuring a guide portion between the groove and tapered surface, along with recesses and cutout portions, allows for attitude correction and removal of foreign substances without forced alignment, preventing seizure by idling and removing large spatters and coated films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guide portion is added to correct bolt attitude, then oblique insertion seizure is suppressed, but device complexity increases
Solution Approach 1:
The bolt is segmented into distinct functional zones: a guide portion at the distal end for attitude correction, a tapered surface for foreign substance removal, and a threaded portion for fastening. This segmentation allows each segment to perform its specific function independently, resolving the contradiction by adding only the necessary guide portion without over-complicating the entire bolt structure.
Solution Approach 2:
The guide portion performs preliminary attitude correction before the threaded portion engages with the internal thread. By pre-aligning the bolt axis with the internal thread axis through the guide portion's geometry, the subsequent fastening operation proceeds smoothly without oblique insertion, thus suppressing seizure while maintaining relatively simple structure.
2Reliability
If multiple cutout shapes are provided to remove foreign substances, then seizure due to biting of foreign substances is suppressed, but manufacturing precision requirements increase
Solution Approach 1:
Foreign substances are extracted from the fastening interface by the guide portion and tapered surface features. The guide portion's geometry and the tapered surface work together to physically remove or prevent foreign substances from interfering with thread engagement, suppressing seizure without requiring high-precision cutout shapes.
Solution Approach 2:
The bolt features local quality variations: the guide portion has specific dimensional characteristics for attitude correction, while the tapered surface has a gradual angle for foreign substance removal. These localized features address specific problems (oblique insertion and foreign substance interference) without requiring high precision throughout the entire bolt, thus reducing overall manufacturing precision requirements.
3Ease of operation
If the guide portion forcibly catches the internal thread for attitude correction, then oblique insertion is corrected, but seizure may occur due to excessive force
Solution Approach 1:
The guide portion provides dynamic attitude correction rather than forced alignment. Its geometry allows the bolt to naturally self-align with the internal thread through gradual engagement, correcting oblique insertion without applying excessive force that could cause seizure. The correction process is flexible and adaptive to the actual insertion conditions.
Data Source
Figure 1~2(b)
Figure 3~4
Figure 5~6(b)
AI summary
The object of the present invention is to provide a bolt 1 which can more effectively suppress occurrence of seizure due to both oblique insertion and biting of foreign substances. The bolt 1 includes a tapered surface 11, a guide portion 12, and a threaded portion 13 in order from a distal end side and further includes a plurality of recesses 111 provided on the tapered surface and a plurality of cutout portions 131 provided at a distal end portion of the threaded portion 13.