Stud Bolt Knurling for Hermetic Sealing
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Solution Overview
Problem
Conventional stud bolt structures for hermetic sealing in containers with pressure differences are complex, prone to manufacturing difficulties, and often result in weak convex portions, deformation, and incomplete insertion, leading to inconsistent joint strength and sealing issues.
Innovation Solution
A stud bolt design featuring a bolt head portion, a bolt shoulder portion with a knurling portion that includes projecting and groove portions, and a bolt base portion with a smoother surface, where the bolt shoulder portion's diameter is smaller than the bolt head portion, and the bolt base portion's height is optimized to ensure proper insertion and sealing, reducing manufacturing complexity and enhancing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If convex portions are formed on the bolt head end surface to eat into the attachment plate, then hermetic seal is improved, but the convex portions become weak and deform during staking
Solution Approach 1:
The invention applies different surface treatments to different regions of the bolt head end surface. The knurling portion has a rough surface with projecting portions that eat into the attachment plate for hermetic seal, while the bolt base portion has a smooth surface that prevents deformation. This local differentiation of surface quality resolves the contradiction between achieving seal and maintaining strength.
2Reliability
If the bolt structure includes multiple convex portions and recessed portions for sealing, then hermetic seal is improved, but the manufacturing process becomes complicated and difficult
Solution Approach 1:
The bolt head end surface is segmented into two distinct portions: a knurling portion with projecting portions for sealing and a bolt base portion with a smooth surface. This segmentation allows each portion to be optimized for its specific function while simplifying the overall manufacturing process compared to forming multiple separate convex and recessed features.
3Productivity
If the bolt structure is simplified for easier manufacture, then productivity is improved, but the hermetic seal precision deteriorates
Solution Approach 1:
The knurling portion is designed with a specific rough surface texture that provides effective hermetic seal through projecting portions that eat into the attachment plate. This localized quality enhancement at the sealing interface achieves high seal precision without requiring complex overall bolt structures, thus maintaining manufacturing efficiency.
4Reliability
If the knurling portion projects beyond the head end surface for sealing, then hermetic seal is improved, but the projecting portions interfere with the attachment plate during staking causing incomplete insertion
Solution Approach 1:
The invention carefully controls the depth and distribution of the knurling portion's projecting portions, ensuring they provide sufficient seal engagement while remaining shallow enough to avoid interfering with the staking process. The bolt base portion's smooth surface further ensures proper insertion by preventing premature contact with the attachment plate.
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
The design achieves a high-precision hermetic seal, improves joint strength consistency, reduces defects, and maintains cost-effectiveness while simplifying the manufacturing process, ensuring stable and uniform sealing performance.
Implementation Method 1
at least part of which eats into the container during staking
Implementation Method 2
has a peripheral surface that is smoother than the knurling portion
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
A stud bolt (1) is disposed with a bolt head portion (2), a bolt shoulder portion (3) whose diameter is smaller than the diameter of the bolt head portion (2), and a thread portion (4b) whose diameter is smaller than the diameter of the bolt shoulder portion (3), wherein the bolt shoulder portion (3) includes a knurling portion (3b) that includes projecting portions (3b1) and groove portions (3b2) on its outer periphery and at least part of which eats into a container (10) during staking and a bolt base portion (3a) that is disposed between the knurling portion (3b) and the bolt head portion (2) and has a peripheral surface that is smoother than the knurling portion (3b).