Overmolded Leaf Spring Non-Return Valve Housing
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Solution Overview
Problem
Existing non-return valves for internal combustion engines, particularly in exhaust gas recirculation lines, face high assembly and production costs, durability issues due to loose attachments, and positional inaccuracies leading to leaks, despite efforts to minimize components and enhance tightness.
Innovation Solution
A non-return valve design featuring a plastic injection-molded housing with overmolded leaf spring elements, eliminating the need for additional components and assembly, and ensuring tolerance-free positioning through precise molding, combined with a sealing element and integrated stop elements for enhanced durability and sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leaf spring elements are attached to the housing using additional components (screws, clips, or separate parts), then the attachment is more secure and durable, but the assembly complexity and production costs increase
Solution Approach 1:
The patent combines the housing and leaf spring elements into a single integrated injection-molded component. The leaf spring elements are directly molded as part of the housing structure, eliminating the need for separate attachment components like screws, clips, or adhesives. This merging of parts achieves secure attachment while reducing component count and assembly complexity.
Solution Approach 2:
The housing serves multiple functions: it provides structural support, acts as the mounting base for leaf spring elements, and integrates the valve seat surfaces. The injection molding process simultaneously creates all these features in one operation, making the housing a multi-functional component that eliminates the need for separate mounting structures.
2Ease of manufacture
If the housing is assembled from multiple separate parts, then manufacturing and assembly flexibility is improved, but positional accuracy and sealing tightness deteriorate due to tolerance accumulation
Solution Approach 1:
The patent merges the housing and valve seat surfaces into a single monolithic injection-molded part. This eliminates the interfaces between separate parts where tolerance accumulation would occur, ensuring precise positioning of leaf spring elements relative to valve seats and achieving reliable sealing without assembly-related positional errors.
Solution Approach 2:
The injection molding process preliminarily establishes the precise geometric relationships between all components during the manufacturing process itself. The valve seat surfaces and leaf spring element positions are defined with high precision in the mold cavity, ensuring accurate positioning is built into the part geometry rather than achieved through tight assembly tolerances.
3Adaptability or versatility
If traditional multi-part construction is used, then design flexibility is improved, but assembly time and production costs increase
Solution Approach 1:
The patent combines multiple traditionally separate components (housing, valve seats, mounting structures) into a single injection-molded part. This eliminates all assembly steps between these components, dramatically increasing production speed while the mold design maintains the necessary functional flexibility for different valve configurations.
Solution Approach 2:
The patent replaces the mechanical assembly system (multiple parts fastened together with screws, clips, or adhesives) with a single molded part system. The injection molding process substitutes for mechanical assembly operations, producing the complete valve body in one manufacturing cycle rather than requiring multiple assembly steps.
4Reliability
If stop elements are provided to prevent leaf spring overload, then valve durability is improved, but the valve requires additional components and assembly steps
Solution Approach 1:
The patent integrates the stop elements directly into the housing structure through injection molding. These stop features are formed as built-in geometric elements of the housing that physically limit the travel of leaf spring elements, preventing overload without requiring separate stop components or additional assembly steps to install them.
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 high tightness and durability with reduced assembly and production costs, ensuring quick operation and preventing leaf spring overload, while maintaining precise positioning and sealing without additional assembly steps.
Implementation Method 1
the leaf spring element is overmolded at one end by the plastic forming the housing with the flow cross section during the injection molding of the housing in such a way that this overmolded end of the leaf spring element is attached to the housing by the plastic
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to non-return valves for gas-conducting lines in the field of internal combustion engines, having a housing (6) with flow cross-sections (2) that are controlled by leaf spring elements (18), are known, but are often complex to manufacture and assemble, and are not sufficiently tightly sealed in the closed state. According to the invention the housing (6) is an injection-moulded plastic part and the leaf spring element (20) is surrounded at one end (22) by plastic material in such a manner that said end (22) of the leaf spring element (20) is fastened to the housing by the plastic material. The non-return valve is produced by punching out leaf spring elements (20), placing the leaf spring elements (20) in a moulding tool that replicates the shape of the housing (6), and the housing (6) is injection-moulded in the moulding tool, wherein ends (22) of the leaf spring elements (20) pointing to a base surface (8) are encapsulated in plastics material. Said method results in low production costs combined with good sealing of the valve in the closed state.