Insert-Cast Cylinder Liner Structure for Void-Resistant Joining
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Solution Overview
Problem
The joining strength between a cylinder liner and a cylinder block is insufficient due to voids formed at the joint portion, particularly in gravity casting and low-pressure permanent mold casting, where the casting material fails to adequately distribute to protrusion-to-protrusion areas on the outer periphery of the cylinder liner.
Innovation Solution
The cylinder liner features a specific arrangement of protrusions on its outer periphery, with a molten metal running index (YI) between 2.2 and 14.5, controlling the distance between adjacent protrusions, the area of top portions, and the space between them, ensuring effective distribution of molten metal and reducing voids at the interface with the cylinder block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If protrusions are provided on the outer periphery of the cylinder liner to improve joining strength, then the joining strength with the cylinder block is improved, but voids are formed at the joint portion due to insufficient distribution of casting material
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric parameters of the protrusions (height, diameter, spacing) to control the flow of molten metal. Specifically, the protrusions are designed with controlled dimensions and distribution patterns that allow molten metal to adequately fill the spaces between protrusions during casting, preventing void formation while maintaining joining strength.
Solution Approach 2:
The patent applies local quality by creating non-uniform distribution of protrusions on the cylinder liner outer periphery. The protrusions are strategically positioned with varying spacing and dimensions in different regions to match the local flow characteristics of molten metal during casting, ensuring adequate metal distribution in areas prone to void formation while maintaining overall joining strength.
2Ease of manufacture
If gravity casting or low-pressure permanent mold casting is used, then manufacturing complexity is reduced, but molten metal fails to distribute adequately to protrusion-to-protrusion areas
Solution Approach 1:
The patent modifies the protrusion parameters (height, diameter, spacing) to be optimized for gravity and low-pressure casting conditions. The protrusions are designed with dimensions and spacing that allow molten metal to flow adequately between them under the relatively low pressure of these casting methods, ensuring complete filling without requiring high-pressure permanent mold casting.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the protrusion geometry and distribution pattern on the cylinder liner before casting to anticipate and guide molten metal flow. The protrusions are strategically designed to create flow paths that facilitate adequate metal distribution during the casting process, preventing void formation before it occurs.
Data Source
AI summary
An object of the present invention is to provide a cylinder liner for insert casting that can improve the joining strength between a cylinder liner and a cylinder block by reducing voids generated between the cylinder liner and the cylinder block.The above-described problem can be solved when the molten metal running index YI defined by the following Formula (1) is from 2.2 to 14.5.Molten metal running index YI=[area ratio St (%) of top portions of protrusions×molten metal infiltration volume V (mm3)/surface area A (mm2) of cylinder liner base]/average surface-to-surface distance Pav between top portions of protrusions (mm) (1).