Cylinder Block Protrusion for Coating Adhesion
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Solution Overview
Problem
Conventional methods for minimizing cylinder block weight to improve fuel consumption face challenges in ensuring a sufficient margin for edge portion removal to prevent detachment of sprayed coatings on the crankcase side.
Innovation Solution
A protrusion is formed at the crankcase-side edge of the cylinder bore, extending towards the crankcase, with a thinner tip portion that is removable along with the sprayed coating, enhancing adhesion and allowing for miniaturization while maintaining a sufficient removal margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the cylinder block is minimized to reduce weight, then fuel consumption is improved, but the margin of the inner surface of the cylinder bore to be removed becomes insufficient to prevent detachment of the sprayed coating
Solution Approach 1:
A protrusion is formed at the crankcase-side edge of the cylinder bore before thermal spraying. This protrusion extends toward the crankcase and provides an additional surface area for the sprayed coating to adhere to. By preparing this protrusion in advance, the coating gain (the portion of coating that would otherwise detach) is extended into the protrusion region, ensuring sufficient adhesion margin even when the overall cylinder bore diameter is reduced for weight reduction.
2Reliability
If the edge portion of the cylinder bore is removed to prevent detachment of the sprayed coating, then coating stability is improved, but the cylinder block size increases
Solution Approach 1:
Instead of removing material from the cylinder bore edge to prevent coating detachment, the invention inverts the approach by adding a protrusion that extends toward the crankcase. This protrusion is then removed together with the coating gain portion after spraying. The inversion allows the removal margin to be sufficient while the protrusion itself compensates for the space, enabling miniaturization of the overall cylinder block.
3Manufacturing precision
If a protrusion is formed and then removed together with the sprayed coating, then sufficient removal margin is ensured, but the manufacturing process becomes more complex
Solution Approach 1:
The formation of the protrusion is merged with the existing cylinder bore machining process. The protrusion is formed by machining the crankcase-side edge of the cylinder bore to extend toward the crankcase, which can be integrated into the standard bore preparation steps. After thermal spraying, the protrusion together with the coating gain portion is removed in a single machining operation, combining multiple functions into streamlined process steps.
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 approach ensures stable adhesion of the sprayed coating, reduces the risk of detachment, and allows for downsizing of the cylinder block without increasing its size, while also improving production efficiency and reducing maintenance costs.
Implementation Method 1
thermal spraying to form sprayed coatings on inner surfaces of cylinder bores is being considered
Data Source
Figure 1
Figure 2(a)~2(d)
Figure 3~4
AI summary
A method for processing a cylinder block is disclosed, wherein a protrusion protruding toward a crankcase is provided at a crankcase-side edge of a cylinder bore and a sprayed coating is formed on an inner surface of the cylinder bore and an inner surface of the protrusion continuous with the inner surface of the cylinder bore. After forming the sprayed coating, at least part of the protrusion is removed together with the sprayed coating formed on the inner surface of the protrusion. Accordingly, even in the case of removing the edge portion of the cylinder bore on the crankcase side, a sufficient margin to be removed can be ensured while a reduction in size of the cylinder block is achieved.