Rolling Tool with Dual Elements for Cylinder Surface Roughening
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Solution Overview
Problem
Existing machining tools for curved workpiece surfaces, such as those in internal combustion engine cylinders, face issues with hard material grains detaching due to excessive forces and plastic deformation during the rolling process, which affects the stability of the surface structure and coating retention.
Innovation Solution
A machining tool with two rotatable rolling elements, where the second rolling element with a smooth surface precedes the first rolling element with a rough surface structure, allowing for axial displacement and ensuring that the hard material grains do not detach, by providing a pre-pressing action that prevents material leaching and maintains the rough surface integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high contact pressure is applied during rolling to create rough surface structure, then surface roughening effect is improved, but hard material grains detach from the matrix composite
Solution Approach 1:
The patent applies preliminary action by introducing grooves into the cylinder running surface before the rolling process. These grooves serve as stress relief features that prevent excessive force buildup during rolling, thereby preventing hard material grains from detaching while still achieving the desired rough surface structure for coating retention
Solution Approach 2:
The patent segments the rolling contact surface by introducing grooves that divide the continuous surface into discrete zones. This segmentation allows controlled stress distribution during rolling, preventing the excessive forces that cause grain detachment while maintaining effective roughening in the working sections
2Reliability
If rough surface structure is created by local deformation, then coating retention is improved, but plastic deformation of the rough surface structure occurs
Solution Approach 1:
The grooves are introduced as a preliminary action before rolling to create a pre-conditioned surface geometry. This preliminary structuring allows the subsequent rolling process to create stable rough surface features without excessive plastic deformation, as the grooves provide stress relief paths
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
This solution ensures reliable and precise machining of the workpiece surface, preventing material leaching and maintaining a stable rough surface structure, even when reversing the direction of advancement, thereby ensuring effective surface treatment and coating retention.
Implementation Method 1
The contact pressure is adjusted in such a way that a rough roll embossing structure is produced during rolling through local deformation of the workpiece material without material removal
Implementation Method 2
a rough roll embossing structure is produced during rolling through local deformation of the workpiece material
Implementation Method 3
The working sections with a rough surface structure provided in WO 2012/084612 A1 typically have grains of hard material which are arranged in a matrix of softer material
Data Source
Figure 1
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AI summary
The invention relates to a machining tool (10), in particular a rolling tool, for machining a workpiece surface (11), in particular a curved inner surface of a bore in a workpiece, comprising a tool body (12) defining a tool axis (13), and at least one first rolling element (21) carried by the tool body (12), which is rotatable about a first rolling element axis (22) and has a first outer surface (23), wherein the first outer surface (23) has a rough surface structure in at least one working section (24) intended for rolling contact with the workpiece surface (11).The invention is characterized in that at least one second rolling element (31) is provided, which is rotatable about a second rolling element axis (32) and has a second outer surface (33), wherein the second outer surface (33) has a distance (r1) to the tool axis (13) in at least one working section (34) intended for rolling contact with the workpiece surface (11), which is less than the distance (r2) of the working section (24) of the first rolling element (21).