Overmoulded Component with Elastic Sealing Element
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Solution Overview
Problem
Existing overmolding techniques for metallic base parts in fuel injection devices are insufficiently tight due to differing coefficients of expansion, leading to micro-gaps and potential corrosion, especially under temperature fluctuations.
Innovation Solution
A component comprising a base part and a sealing element, where the sealing element is elastically deformed and clamped between the base part and the encapsulation, creating a compressed gas space that enhances tightness and robustness against temperature changes and environmental influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a plastic encapsulation is used to coat a metallic base part, then corrosion protection is improved, but tightness is worsened due to micro-gaps caused by different coefficients of expansion
Solution Approach 1:
The patent introduces a sealing element with specific local properties (elasticity, compressibility) at the interface between the metallic base part and plastic encapsulation. This localized sealing structure compensates for the global mismatch in thermal expansion coefficients, preventing micro-gap formation while maintaining overall corrosion protection.
Solution Approach 2:
The sealing element acts as an intermediary component between the metallic base part and the plastic encapsulation. It mediates the thermal expansion differences by deforming elastically, thereby maintaining tight contact and preventing liquid or gaseous media penetration while preserving the corrosion protective function.
2Reliability
If a sealing labyrinth with recesses is used to improve tightness, then liquid/gas penetration is reduced, but tightness remains insufficient under temperature fluctuations
Solution Approach 1:
The sealing element is designed to be dynamically adaptable through elastic deformation. Unlike static sealing labyrinths, this sealing element can change its shape and position in response to temperature fluctuations and relative movements, maintaining effective sealing under varying thermal conditions.
Solution Approach 2:
The sealing element utilizes changes in its physical parameters (elastic deformation, compressibility) in response to temperature variations. This allows the sealing structure to adapt its properties dynamically, maintaining tightness across different temperature ranges where rigid labyrinth structures fail.
3Reliability
If the encapsulation is made tightly fitting to ensure tightness, then sealing is improved, but the component cannot accommodate temperature fluctuations and relative movements
Solution Approach 1:
The sealing element functions as a flexible component that can deform elastically under compression. This flexibility allows it to maintain tight contact between the base part and encapsulation while accommodating thermal expansion and contraction, as well as relative movements during operation.
Solution Approach 2:
The sealing element is pre-compressed during assembly to create an initial sealing force. This beforehand cushioning ensures that even when temperature fluctuations or movements occur, the sealing element maintains sufficient contact pressure to prevent leakage, as the elastic deformation absorbs the dimensional changes.
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 achieves a high degree of tightness and increased corrosion protection by maintaining the sealing element in an elastically deformed state, ensuring the encapsulation and base part remain secure even under temperature fluctuations and relative movements.
Implementation Method 1
the sealing element is elastically deformed and clamped between the base part and the encapsulation
Implementation Method 2
Within this space is a gas that is compressed in particular. The pressure of the compressed gas also acts on the sealing element
Implementation Method 3
This creates micro-gaps into which liquid or gaseous media can enter, promoted by the capillary effect
Data Source
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AI summary
The present invention relates to a component comprising a base part (2), a sealing element (3) and an overmoulding (5), which extends at least partly around the base part (2) and at least partly around the sealing element (3), wherein the encapsulation (5) keeps the sealing element (3) in an elastically deformed state.