Cast Piston Cooling Channel Openings With Rounded Core Profiles

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Solution Overview

Problem

Existing piston manufacturing methods using lost cores create sharp-edged transitions in the cooling channel area, leading to material stress and potential cracking, and require machining to form openings, which can introduce contaminants.

Innovation Solution

The core extends into the piston mold to create openings with rounded profiles and circumferential beads, eliminating sharp edges and allowing seamless transitions, and is designed to form inlet and outlet openings without the need for post-machining, using a lost core like salt or sand core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a lost core is used to form cooling channels in piston blanks, then the cooling channel can be created without post-machining, but sharp-edged transitions are formed in the material area surrounding the cooling channel, which induce stresses and can lead to cracks

Engineering Contradiction:

Improvecooling channel formationVSAvoidcrack prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The core is designed with a rounded profile that creates a seamless transition from the opening to the cooling channel, eliminating sharp edges. The rounded shape distributes stresses more evenly in the material microstructure, preventing crack initiation while maintaining the cooling channel function.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Manufacturing precision

If machining operations are used to create openings for cooling channels, then precise opening shapes can be achieved, but smaller particles generated during machining can penetrate the cooling circuit of the internal combustion engine

Engineering Contradiction:

Improveopening shape precisionVSAvoidcontaminant penetration

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The opening shape is predetermined by the core design before casting. The core is removed after the piston blank is formed, leaving the opening already shaped without requiring subsequent machining operations that would generate contaminants.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the core is removed after casting and solidification, then the piston blank can be finished to produce the piston, but the core removal process may leave imperfections or require additional processing

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidopening quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The rounded profile of the core ensures that when it is removed after casting, it leaves a clean, seamless opening without sharp edges or imperfections. The curved geometry allows for easy core removal while maintaining high opening quality without additional processing.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentEP3377244B1Cast inflow and outflow openings for cast-steel and cast-iron pistons

Publication Date: 2025.12.31 KS KOLBENSCHMIDT GMBH

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AI summary

Method for producing a piston (8), which has a cooling channel (4) created by means of a lost core (3), wherein, in a casting process using a casting mould into which the core (3) is placed before casting and using a casting melt, a piston blank (1) is cast and, after the casting melt has solidified, the piston blank (1) is removed from the casting mould and the core (3) is subsequently flushed out, and this is followed by the finishing of the cast blank (1) to produce the piston (8), wherein the core (3) extends into a region of the casting mould that forms an inner region of the piston blank (1) and the core (3) is used to form at least one opening having a rounded profile for the cooling channel (4) after the flushing out.