Intermediate Piece Sealing for Nitrided High-Pressure Injection Components
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Solution Overview
Problem
High-pressure components in injection devices for internal combustion engines, which are nitrided for wear resistance, often suffer from embrittlement and cracking due to their hardness, making it difficult to prevent material damage and achieve effective sealing without compromising wear resistance.
Innovation Solution
A connection design that incorporates an intermediate piece with lower hardness between nitrided components, allowing for plastic deformation and acting as a sealing ring to prevent cracking while maintaining wear resistance, using a softer material like steel or copper for the intermediate piece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If components are nitrided to increase wear resistance, then wear resistance is improved, but embrittlement and cracking occur
Solution Approach 1:
The connection assembly is segmented into three distinct components: a first nitrided component, a second nitrided component, and an intermediate piece with different material properties. This segmentation allows each component to have optimized characteristics - the nitrided components provide wear resistance while the intermediate piece provides ductility and prevents cracking.
Solution Approach 2:
Different material properties are applied to different parts of the connection assembly. The first and second components have nitrided surfaces with high hardness for wear resistance, while the intermediate piece has lower hardness and higher ductility. This local differentiation of material properties resolves the contradiction between wear resistance and embrittlement.
2Reliability
If sealing surfaces are pressed together with high force to achieve sealing, then sealing effect is improved, but material damage occurs due to brittleness
Solution Approach 1:
The intermediate piece acts as a mediator between the two nitrided components. It allows the sealing force to be transmitted while its higher ductility prevents material damage and cracking that would occur in the brittle nitrided components. The intermediate piece absorbs the mechanical stress without suffering permanent damage.
3Reliability
If covering areas are protected from nitriding to prevent embrittlement, then embrittlement is reduced, but nitride formation still occurs in covered areas
Solution Approach 1:
The intermediate piece is extracted from the nitriding process entirely. Instead of trying to control nitride formation in covered areas, the solution removes the intermediate piece from the nitriding treatment, using a material that is inherently suitable for the sealing function without requiring surface hardening.
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 effectively prevents cracking and material damage while maintaining wear resistance, achieving a secure and efficient sealing mechanism that allows for plastic deformation of the intermediate piece, ensuring a reliable high-pressure connection.
Implementation Method 1
a material can be used for the intermediate piece that allows plastic deformation of the sealing surfaces of the intermediate piece when the connection is assembled when the sealing edge is pressed into the corresponding sealing surface in the axial direction
Implementation Method 2
nitrated components are often used, which have increased wear resistance
Implementation Method 3
the surfaces of which are hardened and which have sealing surfaces facing one another
Data Source
Figure 1
AI summary
The invention relates to a connection of components (1, 2), carrying high-pressure medium, of an injection device for internal combustion engines, comprising a first component (1) and a second component (2), the surfaces of which are hardened and which have sealing surfaces (4, 5) facing one another, wherein the sealing surfaces (4, 5) on the components facing one another interact with sealing surfaces on an intermediate piece (3) having a passage hole (7) arranged between the first and second components, said intermediate piece having a lower hardness than the sealing surfaces (4, 5) on the first and second components (1, 2), wherein one respective sealing surface of two sealing surfaces interacting with one another has a sealing edge (6).