Internal Thread Plastic Deformation for High-Pressure Sealing
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Solution Overview
Problem
High-pressure fluid-carrying components in internal combustion engine injection devices face challenges with large sealing diameters, leading to increased prestressing forces and dynamic load on threads, which current methods only partially address, especially under high-prestressing conditions.
Innovation Solution
Applying a radial compression force to the tubular end portion of the first component to induce plastic deformation, resulting in a continuously decreasing internal thread diameter and altered stress distribution, thereby reducing thread load and improving load-carrying capacity through a prestressed and predeformed thread geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large sealing diameters are used for high-pressure components, then sealing capability is improved, but thread load and prestressing forces increase
Solution Approach 1:
The patent applies local quality by creating a non-uniform thread geometry where the inner diameter of the internal thread continuously decreases towards the free end. This local variation in thread dimensions optimizes the stress distribution specifically in the threaded region, reducing the notch effect and improving load-carrying capacity without changing the overall sealing diameter of the component.
Solution Approach 2:
The patent changes the geometric parameters of the thread by applying radial compression force to the tubular end portion, transforming it into a prestressed and predeformed state. This parameter change creates a continuously decreasing inner diameter profile, which alters the stress distribution and reduces thread load while maintaining the required sealing capability.
2Ease of manufacture
If conventional thread geometry is used, then manufacturing is simple, but fatigue strength and load-carrying capacity are limited
Solution Approach 1:
The patent applies preliminary action by pre-deforming the tubular end portion through radial compression before the final thread assembly. This preshaping creates a prestressed state that improves fatigue strength and load-carrying capacity in advance, allowing the thread to better withstand dynamic loads and pulsating pressure without compromising manufacturing feasibility.
3Reliability
If high prestressing forces are applied to threaded connections, then sealing reliability is improved, but dynamic load on threads increases
Solution Approach 1:
The patent addresses this contradiction by creating local quality variations in the thread geometry through continuous inner diameter reduction. This localized geometric optimization improves the thread's ability to withstand dynamic loads and pulsating pressure, reducing the negative effects of high prestressing forces while maintaining sealing reliability.
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 method enhances the load-carrying capacity and uniformity of force distribution across thread turns, reducing stress concentrations and improving the overall performance of the threaded connection under high-pressure conditions.
Implementation Method 1
the tubular end portion on the external side is acted upon by a radial compression force allowing a plastic deformation, thus transforming the tubular end portion in such a manner that the internal thread obtains an inner diameter continuously decreasing towards the free end
Data Source
AI summary
In a method for influencing the thread geometry of an internal thread of a first component of an injection device for internal combustion engines, which is provided for carrying high-pressure fluid, wherein the first component has a tubular end portion and an internal thread is formed on the interior surface of the tubular end portion, and a second component having an exterior surface on at least a portion thereof so as to be received in the tubular end portion of the first component wherein the exterior surface is threaded so said second component can be screwed and clamped against a support surface of the first component, and wherein the tubular end portion on the external side is acted upon by a radial compression force allowing a plastic deformation. The tubular end portion is transformed thereby in such a manner that the internal thread obtains an inner diameter (D) continuously decreasing towards the free end.