Pipe Connecting Device Inclined Pressing Surface Stress Distribution
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Solution Overview
Problem
Conventional pipe-connecting devices using an inner ring face challenges in maintaining seal performance and durability due to high stress and deformation, especially during repeated use and in high-temperature conditions, requiring frequent refastening and limited number of uses.
Innovation Solution
The pipe-connecting device features an inclined inner circumferential surface on the union nut that presses the tube with a wide surface, reducing surface pressure and stress concentration, allowing for increased repeated use and improved seal performance by enhancing the wedge action and minimizing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pointed pressing edge is used to press the tube strongly for sealing, then seal performance is improved, but stress concentration and deformation increase leading to limited repeated use
Solution Approach 1:
The pressing portion is designed with different surface characteristics: a pointed pressing edge for localized sealing contact, and a wide inclined inner circumferential surface for distributed stress application. This local quality differentiation allows the tube to be sealed effectively while avoiding excessive stress concentration that would cause deformation and limit repeated use.
Solution Approach 2:
The invention changes the pressing parameters by transitioning from a single-point pressing edge to an inclined surface with a specific angle range (30°-60°). This parameter change distributes the pressing force over a larger area while maintaining effective sealing, thereby reducing stress concentration and enabling repeated use without excessive deformation.
2Reliability
If strong fastening force is applied to prevent tube slipping, then connection security is improved, but worker burden and difficulty in confined spaces increase
Solution Approach 1:
The inclined inner circumferential surface creates a wedge action that converts axial fastening force into radial clamping force. This local geometric feature amplifies the fastening effect, allowing connection security to be achieved with reduced fastening force, thereby decreasing worker burden and improving ease of operation in confined spaces.
3Reliability
If repeated fastening operations are performed to prevent loosening, then connection reliability is maintained, but deformation increases and component replacement becomes necessary
Solution Approach 1:
The inclined surface angle parameter (30°-60°) is optimized to balance two competing requirements: providing sufficient wedge action for connection reliability while minimizing stress concentration that leads to deformation. This parameter optimization allows the connection to maintain reliability over extended periods without excessive deformation, thereby extending service life and reducing the frequency of component replacement.
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
This configuration significantly reduces creep and deformation, enabling the pipe-connecting device to maintain satisfactory seal performance and extend its life by allowing multiple uses beyond conventional limits while reducing the force required for fastening and improving workability.
Implementation Method 1
the pressing portion (12b) is an inclined inner circumferential surface which is inclined in the same direction as the outer-circumferential flared surface (3a), and configured so as to press the tube (4) by a wide surface
Implementation Method 2
configured so as to press the tube (4) by a wide surface... the wedge action and minimizing deformation
Data Source
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AI summary
A pipe-connecting device is provided which is of the type using an inner ring, and which, while maintaining a satisfactory seal performance, is improved so as to be repeatedly used times larger than those in the conventional art, by revising the structure. A pipe-connecting device includes: an inner ring 3 having: an outer circumferential portion 3G having a tip-contracted outer-circumferential flared surface 3a that is to be press-inserted into an end portion 4C of a tube 4 to flare the tube, and an inner circumferential portion 3w constituting a fluid transfer path; a pipe joint body 1 that has a tubular screwing portion 1A having an external thread 7; and a union nut 2 having an internal thread 13 that is screwed with the external thread 7. The inner ring 3 including the tube 4 is inserted into the tubular screwing portion 1A, and the tip-contracted outer-circumferential flared surface 3a is pressed through the tube 4 by a pressing portion 12b of the union nut 2. In the device, the pressing portion 12b of the union nut 2 which presses the tube 4 against the tip-contracted outer-circumferential flared surface 3a is formed into an inclined inner circumferential surface which is inclined in the same direction as the tip-contracted outer-circumferential flared surface 3a with respect to the axis Y of the tubular screwing portion 1A.