Pipe Joint Primary Seal Geometry for Press-Fit Leakage Prevention
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Solution Overview
Problem
The cross-sectional shape of the primary sealing portion in pipe joints is prone to deformation, leading to fluid leakage due to insufficient strength and surface pressure, which hinders the replaceability of fluids in the pipe path.
Innovation Solution
The primary sealing portion is designed with a tapered shape and a flat surface extending from the radially outer end toward the radially inner side, increasing radial thickness at the axially outer end, and an inclined inner circumferential surface to enhance strength and prevent deformation, along with a chamfered corner to facilitate fluid flow away from recesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the primary sealing portion is formed with a tapered shape to facilitate press-fitting, then the ease of manufacture is improved, but the strength at the axially outer end is reduced causing deformation
Solution Approach 1:
The primary sealing portion is designed with non-uniform thickness, being thinner at the axially inner end for ease of press-fitting and thicker at the axially outer end for strength. This local variation in geometric properties resolves the contradiction between ease of manufacture and structural strength.
2Ease of manufacture
If the thickness at the axially outer end of the primary sealing portion is reduced to enable press-fitting, then the ease of manufacture is improved, but the surface pressure is insufficient causing fluid leakage
Solution Approach 1:
The primary sealing portion features localized thickness variation, being thinner at the axially inner end to facilitate press-fitting and thicker at the axially outer end to ensure adequate surface pressure for reliable sealing. This resolves the contradiction between ease of manufacture and sealing reliability.
3Ease of manufacture
If the primary sealing portion is sharply formed at the axially outer end to reduce material, then the ease of manufacture is improved, but the deformation resistance is reduced causing falling down
Solution Approach 1:
The primary sealing portion is designed with varying thickness along its axial length, being thinner at the axially inner end for ease of forming and thicker at the axially outer end for shape stability and deformation resistance. This local geometric differentiation resolves the contradiction between ease of manufacture and shape stability.
Data Source
AI summary
An inner ring 4 of a pipe joint 1 includes a cylindrical body portion 5 having a communication hole 5a for providing communication between flow passage holes 2c and 8a of a joint body 2 and a tube 8, and an annular primary sealing portion 11 projecting from a radially inner side of an axially outer end portion of the body portion 5 toward an axially outer side and to be press-fitted into an annular primary sealing groove 2d formed on the joint body 2. The primary sealing portion 11 is formed so as to be tapered from an axially inner end thereof toward an axially outer end thereof in an axial cross-sectional view, and has a flat surface 11c extending from a radially outer end 11b of the axially outer end thereof toward the radially inner side.