Segmented Quench-Hardened Hole Structure for Wear and Accuracy
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Solution Overview
Problem
Forming an annular quench-hardened region around the outer edge of a hole in a machine component made of steel or cast iron leads to decreased dimensional accuracy due to volume expansion, which is undesirable for wear resistance and functional integrity.
Innovation Solution
A machine component with a circular hole featuring a plurality of first quench-hardened regions arranged apart along a circle surrounding the hole, along with a base region, to minimize the decrease in hole diameter and maintain dimensional accuracy while enhancing wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an annular quench-hardened region is formed around the outer edge of the hole, then wear resistance is improved, but dimensional accuracy of the hole decreases
Solution Approach 1:
The patent divides the continuous annular quench-hardened region into multiple discrete quench-hardened regions arranged along a circle surrounding the hole. This segmentation prevents the formation of a complete annular hardening zone, thereby reducing the overall volume expansion and residual stress that would otherwise distort the hole dimensions, while still providing sufficient wear resistance at critical contact points.
Solution Approach 2:
The patent applies quench hardening locally at specific discrete positions around the hole rather than forming a continuous annular hardening zone. This localized approach concentrates the wear resistance enhancement where it is most needed (at potential contact points with planetary gears) while minimizing the total volume of hardened material, thus reducing overall volume expansion and preserving hole dimensional accuracy.
2Strength
If a quench-hardened region is formed to include the surface and surround the outer edge of the hole, then wear resistance is improved, but volume expansion occurs leading to hole diameter decrease
Solution Approach 1:
The patent segments the quench-hardened regions into multiple discrete zones arranged circumferentially around the hole, rather than forming a continuous annular hardening zone. This segmentation reduces the total volume of hardened material, thereby minimizing the cumulative volume expansion effect while maintaining adequate wear resistance at critical surface locations.
Solution Approach 2:
The patent applies quench hardening partially around the hole perimeter through discrete regions rather than forming a complete annular hardening zone. This partial action provides sufficient wear resistance at the most critical contact points without the excessive volume expansion that would result from complete annular hardening.
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 configuration effectively suppresses the decrease in dimensional accuracy and improves wear resistance by strategically placing quench-hardened regions to prevent overlapping residual stress, thus maintaining the component's functional integrity and accuracy.
Implementation Method 1
an annular quench-hardened region including the surface and surrounding the outer edge of the hole may be formed
Data Source
AI summary
A machine component, made of steel or cast iron and having a circular hole that opens in a first surface, includes a plurality of first quench-hardened regions that include the first surface and are arranged apart from each other along a first circle surrounding the hole when viewed in a plane in a direction perpendicular to the first surface, and a base region that is a region other than the first quench-hardened regions.