Cylinder Bore Coating with Axial Protective Ring
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Solution Overview
Problem
Existing methods for coating engine block cylinder bores result in metal particles overspray contaminating the sealing surface, requiring additional cleaning or machining steps, increasing time and cost.
Innovation Solution
A protective ring is formed axially on the engine block using non-cutting forming techniques, redirecting metal particles radially away from the sealing surface during coating, and subsequently removed to maintain the desired geometry and achieve a clean edge finish.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating lance is inserted into the bore to apply coating particles, then the bore wall receives a protective coating, but metal particles overspray contaminates the sealing surface
Solution Approach 1:
A receiving unit with a collection device is introduced as an intermediary between the coating lance and the sealing surface. This device captures oversprayed metal particles before they can contaminate the sealing surface, allowing the coating process to proceed without direct harmful contact between the coating particles and the sealing area.
Solution Approach 2:
The sealing surface is segmented into a coated area (bore region) and a protected area (sealing surface) using the receiving unit as a physical divider. The collection device creates a spatial separation that allows coating particles to be contained within the bore region while preventing their migration to the sealing surface.
2Manufacturing precision
If the sealing surface is machined again to remove contamination, then the sealing surface is cleaned, but additional time and expense are incurred
Solution Approach 1:
The receiving unit with the collection device is positioned and configured before the coating process begins. This preliminary setup prevents contamination from occurring in the first place, eliminating the need for subsequent cleaning or remachining operations to remove oversprayed particles from the sealing surface.
Solution Approach 2:
The collection device performs a preliminary anti-action by capturing and containing metal particles before they can settle on the sealing surface. This preventive measure counteracts the potential harmful effect of particle deposition, making post-coating cleaning operations unnecessary.
3Reliability
If the receiving unit contacts the sealing surface to capture particles, then particle collection is effective, but the receiving unit itself becomes contaminated
Solution Approach 1:
The collection device is designed to be removable and separable from the receiving unit. After capturing metal particles during the coating process, the collection device can be extracted and removed for cleaning or replacement, preventing permanent contamination of the receiving unit and maintaining its functionality for subsequent operations.
4Productivity
If the protective ring is formed by chipless forming, then the process is simpler and faster, but the protective ring must be removed later to maintain geometry
Solution Approach 1:
The protective ring is designed as a temporary, disposable feature formed by chipless forming. It serves its protective function during the coating process and is then removed by machining. The simplicity and speed of formation outweigh the removal step because the ring prevents costly contamination and maintains bore geometry during coating, making it a worthwhile temporary structure.
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 method ensures a low-contamination, efficient coating process that prevents metal particle deposition on the sealing surface, reducing post-coating processing needs and ensuring a stable, long-lasting coating on the bore wall.
Implementation Method 1
a coating device with a movable coating lance, through which a metal plasma jet is generated to form a coating of metal particles
Implementation Method 2
an axially projecting protective ring is formed by chipless forming by means of a pressing element which is pressed into the workpiece
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for coating the wall (14) of a bore (12) in a workpiece (10), in particular a cylinder bore in an engine block, in which a coating lance (52) is inserted into the bore (12) while dispensing coating particles, thereby providing the bore wall (14) with a coating. According to the invention, an annular protective ring (20) is provided at the edge of the bore prior to coating, which projects axially towards one side of the workpiece. The invention further comprises an engine block in which an axially projecting protective ring is integrally formed on a base body of the engine block at one edge of the at least one cylinder bore.