Internal Pipe Embossing With Wedge Stamps for Complex Valve Stem Structures
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Solution Overview
Problem
Current methods lack a viable solution for attaching structured surfaces to the inside of pipes and valve stems, particularly for materials that cannot be cast and for creating non-uniform internal structures, which limits the ability to enhance heat transfer and surface area in internally cooled poppet valves.
Innovation Solution
An embossing tool and method using multiple embossing stamps with curved surfaces and a wedge mechanism to imprint structures on the inside of pipes and valve stems, allowing for the creation of complex internal geometries that cannot be achieved with conventional tools, including those that prevent the mandrel from being pulled out, enabling enhanced heat transfer and surface area expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional casting methods are used to create internal structures, then structures can be created in tubes, but this is only possible with tubes made of materials that can be cast and cores must be destroyed for removal
Solution Approach 1:
The embossing tool is extracted from the tube after the embossing process is complete. The tool features a withdrawal cone that allows it to be pulled out without destroying any core structures, unlike casting methods where cores must be broken apart for removal.
Solution Approach 2:
The embossing tool acts as an intermediary device that transfers the structure onto the tube interior surface through embossing pressure, then withdraws cleanly. This mediator approach avoids the need for permanent core structures that would need to be destroyed.
2Ease of manufacture
If broaching or hammering on mandrels is used to produce internal structures, then structures can be created in barrels, but this is only possible for continuous or uniform structures and mandrels are destroyed or pulled out
Solution Approach 1:
The embossing tool is designed to be extracted from the tube after embossing. The withdrawal cone geometry allows the tool to be pulled out cleanly without damaging the tube or the embossed structure, resolving the mandrel integrity issue.
Solution Approach 2:
The structure is embossed onto the tube interior surface before the tool is withdrawn. This preliminary action ensures the structure is already formed and adhered to the tube wall, allowing clean removal of the tool without compromising the structure.
3Manufacturing precision
If conventional hammering or long forging machines are used, then grooves can be formed into the shape of grooves on the inside of the barrel, but this puts a lot of stress on the mandrel and mandrels are pulled out or forged into the barrel
Solution Approach 1:
The embossing tool uses multiple embossing stamps (at least three) distributed around the circumference, each applying localized pressure to form the structure. This segmentation distributes the force across multiple contact points rather than concentrating it on a single mandrel surface.
Solution Approach 2:
The embossing stamps feature curved embossing surfaces that conform to the tube's interior geometry. This curvature allows the stamps to apply pressure evenly across the embossing surface, distributing forces and preventing localized stress concentration on the tool.
4Ease of manufacture
If structured mandrels are inserted and material is pressed onto the mandrel, then longitudinal structures can be provided in valve cavities, but this is only suitable for tubes with short length and large diameter
Solution Approach 1:
The embossing tool is designed to be inserted into and withdrawn from the tube dynamically. The withdrawal cone and flexible stamp arrangement allow the tool to adapt to tubes of various lengths and diameters, overcoming the limitations of fixed structured mandrels.
Solution Approach 2:
The embossing stamps can be arranged in multiple dimensions within the tool assembly, allowing the tool to reach and emboss structures in tubes of various sizes. The multi-dimensional arrangement of stamps provides versatility for different tube geometries.
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 creates complex internal structures within pipes and valve stems, enhancing heat transfer and surface area, which is not possible with conventional methods, and allows for the removal of the embossing tool without destroying the core, thus overcoming the limitations of existing technologies.
Implementation Method 1
Each of the at least three embossing stamps comprises, in the radial direction, an outer stamping or embossing surface provided with a structure... The stamping surface is curved about a straight line that is parallel to a center axis of the embossing tool
Data Source
Figure 1A~2D
Figure 3A~3B
Figure 3C~3D
AI summary
The invention relates to an embossing tool (4) for embossing a structure in an inside of a pipe, comprising at least three embossing stamps (6) and a wedge (20), wherein each of the at least three embossing stamps (6) has an outer, in the radial direction, stamp or embossing surface (16), which has a structure (18), which corresponds to a negative form of the structure to be embossed, wherein the stamp surface (16) is curved about a straight line, which is parallel to the center axis, two flank surfaces (14), which are at an angle to each other, and the section line of which is parallel to the center axis, and a wedge inner surface (10), which is inclined relative to the center axis and intersects each of the two flank surfaces (14) at an identical angle, wherein the wedge has at least three wedge outer surfaces (22), each of which have the same angle relative to the center axis, and wherein each of the wedge outer surfaces (22) have an identical angle relative to the respectively adjacent wedge outer surfaces (22).