Valve Shaft Seal with Metal Support Form-Fit
Solution Overview
Problem
Existing valve shaft seals in internal combustion engines face challenges with high pressures, as they tend to move off the guide or tear, especially at pressures above 15 bar, and rubber material embrittlement affects holding force over time, leading to inefficiencies and increased costs.
Innovation Solution
A seal design featuring a sealing lip of elastomer with a supporting structure made of a different material, such as metal, that forms a form-fit connection with the guide element through partial plastic deformation, providing enhanced holding force and sealing efficacy even at increased pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber seal is used with a guide element, then sealing is achieved, but the seal moves off the guide at pressures above 15 bar
Solution Approach 1:
The seal is divided into two distinct parts: a rubber sealing lip for sealing and a metal supporting structure for mechanical retention. This segmentation allows each component to perform its specialized function - the rubber provides sealing while the metal provides form-fit connection and resistance to high pressures
Solution Approach 2:
The invention uses a composite structure combining rubber (elastomer) and metal materials. The rubber sealing lip provides sealing properties while the metal supporting structure provides mechanical strength and form-fit connection capability, creating a composite seal that overcomes the limitations of using only rubber
2Reliability
If rubber material is used for the seal, then sealing is achieved, but the rubber material tears and embrittles over time
Solution Approach 1:
By separating the sealing function (rubber lip) from the structural support function (metal supporting structure), the invention eliminates the need for rubber to provide both sealing and mechanical strength, allowing the metal component to bear mechanical loads and prevent tearing
Solution Approach 2:
Different materials are used for different parts of the seal: rubber for the sealing lip where flexibility and sealing are needed, and metal for the supporting structure where strength and resistance to embrittlement are required
3Reliability
If a metal piece with undercut is used to clamp the rubber seal, then increased pressure operation is possible, but manufacturing costs increase
Solution Approach 1:
The invention merges the sealing lip and supporting structure into a single integrated seal component, eliminating the need for separate metal clamping pieces and reducing the number of parts. This integration simplifies manufacturing while maintaining pressure resistance through the form-fit connection of the metal supporting structure
4Reliability
If a spring-loaded metal piece is used to generate clamping force, then sealing is achieved, but the compressive forces from 15 bar cannot be held
Solution Approach 1:
The metal supporting structure is pre-formed with a specific geometry that enables it to create a form-fit connection with the guide element during assembly. This preliminary shaping allows the seal to automatically generate the necessary mechanical retention without requiring additional spring-loaded components
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 maintains a sealing effect at pressures up to 20 bar or more, reducing the risk of seal displacement and material failure, while potentially reducing elastomer usage and manufacturing complexity.
Implementation Method 1
The supporting structure is configured to provide a form fit in the axial direction by at least a partial plastic deformation in the radial direction, directly between the supporting structure and a guide element of the valve shaft
Data Source
AI summary
Embodiments relate to a seal for sealing a valve shaft in an internal combustion engine. The seal includes a sealing lip of an elastomer which is configured to be in contact with a shell surface of the valve shaft perpendicular to a radial direction. The seal further includes a supporting structure firmly connected to the sealing lip and made of a material different from the elastomer of the sealing lip which is configured to create a form-fit in the axial direction directly between the supporting structure and a guide element of the valve shaft by an at least partial plastic deformation in the radial direction.