Union Nut Expansion Region for Leak-Resistant Line Connections
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Solution Overview
Problem
Ball or tapered screw connections, such as those in motor vehicle fuel systems, experience reduced pressing force due to heat cycles and stiffness, leading to potential leakages and susceptibility to unintentional opening, with small reverse rotation angles causing complete loss of prestress and difficulty in identifying small leaks.
Innovation Solution
A nut with an expansion region featuring transversely or obliquely oriented cutouts that allow for elastic deformation along the longitudinal direction, preventing radial widening and unintentional loosening, while maintaining a constant sealing force and large elastic reserve, and facilitating leak testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the nut is made stiff to maintain structural integrity, then structural strength is improved, but pressing force is reduced due to heat cycles and settling losses
Solution Approach 1:
The nut is divided into a stiff outer shell and a deformable inner expansion region separated by cutouts. This segmentation allows different regions to have different mechanical properties: the outer shell maintains structural strength while the inner expansion region deforms elastically to maintain pressing force.
Solution Approach 2:
Different regions of the nut are given different mechanical properties. The outer shell and end regions are made stiff for structural integrity, while the expansion region in the middle is made elastically deformable through cutouts to compensate for pressing force loss.
2Force
If the nut is made elastic to compensate for pressing force loss, then pressing force is improved, but radial widening occurs causing unintentional loosening
Solution Approach 1:
The nut structure is segmented into stiff end regions and a deformable expansion region. The stiff end regions prevent radial widening and unintentional loosening, while the expansion region can deform axially to maintain pressing force.
Solution Approach 2:
The cutouts are oriented transversely and/or obliquely with respect to the longitudinal direction, creating asymmetric deformation characteristics that favor axial compression over radial expansion, thus maintaining connection stability.
3Duration of action of moving object
If cutouts are oriented transversely to support axial extension, then elastic deformation is improved, but radial widening is enabled causing unintentional loosening
Solution Approach 1:
The cutouts are oriented at specific angles (transversely and/or obliquely) to create asymmetric deformation characteristics. This orientation allows axial extension while the stiff end regions and specific geometry prevent radial widening that would cause loosening.
Solution Approach 2:
The cutout orientation and geometry are specifically designed in the expansion region to enable axial elasticity while the overall nut structure, including end regions, maintains radial stability to prevent unintentional loosening.
4Ease of manufacture
If the nut design is simplified to reduce manufacturing complexity, then ease of manufacture is improved, but leak detection capability is reduced
Solution Approach 1:
The expansion region with cutouts serves multiple functions: it maintains pressing force through elastic deformation, provides leak detection capability through medium escape paths, and simplifies manufacturing compared to complex sensing systems. One structure achieves multiple objectives.
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 solution provides a robust and reproducible screw connection with increased frictional torque, preventing unintentional loosening and ensuring consistent sealing force, while allowing for easy leak testing through the designed expansion region.
Implementation Method 1
The expansion region is expediently configured and designed or formed in such a way that the nut can deform elastically in said region, in particular axially, that is to say along the longitudinal direction
Implementation Method 2
a more or less hard ball is pressed against a sealing surface by means of a union nut, as a result of which plastic deformation of the ball or sealing surface, which is for example formed as a tapered section, occurs at the contact circle between the sealing surface and the ball
Implementation Method 3
The solution provides a robust and reproducible screw connection with increased frictional torque, preventing unintentional loosening
Data Source
AI summary
A nut, in particular a union nut for a line connection, extends along a longitudinal direction, wherein the nut has at least one expansion region. The expansion region has circumferentially one or more recesses which extend transversely and/or obliquely to the longitudinal direction.