Pipe Spool Clearance Structure to Prevent Cracks
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Solution Overview
Problem
The existing spool designs for pipes lack clearance between the first and second portions, leading to excessive bending and stress concentration at the top, which increases the likelihood of cracks and variation in spool height.
Innovation Solution
Incorporating a clearance between the first and second portions at the top region of the spool while ensuring they abut each other in the base region, with the option of a straight part for surface contact to lock with another member, and using a spool forming die with specific surfaces to achieve this configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If no clearance is provided between the first portion and the second portion of the spool, then the spool height is reduced and the structure is more compact, but excessive bending occurs at the top of the spool leading to stress concentration and crack generation
Solution Approach 1:
The patent applies local quality by providing clearance specifically in the top region of the spool where bending occurs, while maintaining no clearance (abutment) in the base region. This localized differentiation allows the top region to accommodate bending stresses without crack generation, while the base region maintains structural compactness and proper height control.
2Reliability
If clearance is provided between the first portion and the second portion at the top region, then stress concentration and crack generation are reduced, but variation in spool height increases
Solution Approach 1:
The invention resolves this contradiction by applying local quality - clearance is provided only in the top region of the spool where bending stresses occur, while the base region maintains no clearance for consistent height control. This localized approach allows stress relief where needed without compromising overall manufacturing precision.
3Adaptability or versatility
If the spool is formed in a part that has undergone pipe expansion or contraction, then the spool can be integrated with work-hardened sections, but stress concentration and crack generation increase due to work-hardening problems
Solution Approach 1:
The patent addresses this issue by changing the geometric parameter of the spool - specifically by providing clearance in the top region. This parameter change reduces stress concentration in the work-hardened area where the spool is formed, thereby preventing crack generation while maintaining the ability to integrate with pipe expansion or contraction processes.
Data Source
AI summary
A pipe extending from a first side toward a second side includes a side wall and a spool. The spool formed in the side wall is bent so as to protrude from an outer circumferential surface of the pipe, and extends to surround the outer circumferential surface. The spool includes a first portion located on the first side and a second portion located on the second side. There is a clearance between the first portion and the second portion in a top region of the spool, and the first portion and the second portion substantially abut each other in a base region.