Bearing Ring Induction Hardening for Uniform End-Zone Quenching

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Solution Overview

Problem

Existing induction hardening methods for large rolling-element bearing rings fail to achieve uniform hardness due to inadequate quenching in the end zone, leading to non-uniform microstructure and suboptimal hardness results.

Innovation Solution

An induction-hardening system with a first and second inductor, each with a heating element and quenching device, is designed to traverse the bearing ring, supplemented by a third quenching device in the end zone to ensure uniform heating and quenching, with quenching devices adapted to the bearing ring's contour for seamless transition and exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two inductors traverse the bearing ring in opposite directions with quenching sprayers pivoted to inject quenching fluid below the inductors, then quenching in the end zone becomes possible, but sufficient space cannot be provided for pivoting, resulting in non-uniform quenching and microstructure differences

Engineering Contradiction:

Improvequenching capability in end zoneVSAvoidspace requirement for sprayer pivoting

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The quenching system is divided into multiple independent quenching devices (first quenching device associated with first inductor, second quenching device associated with second inductor, and third quenching device for end zone). Each quenching device operates independently in its designated zone, eliminating the need for complex pivoting mechanisms while ensuring uniform quenching coverage throughout the bearing ring including the end zone.

Inventive Principle:

Principle #1Segmentation

2Area of stationary object

If quenching sprayers are designed to pivot for quenching in both process zone and end zone, then quenching coverage is extended, but the bearing ring cannot be uniformly quenched and optimum hardness result cannot be achieved

Engineering Contradiction:

Improvequenching coverage areaVSAvoidhardness uniformity

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

Different quenching devices are positioned and configured for their specific zones: the first and second quenching devices operate in their respective process zones following the inductors, while the third quenching device is specifically positioned in the end zone. This localized approach ensures each zone receives appropriate quenching treatment, achieving uniform hardness throughout the entire bearing ring.

Inventive Principle:

Principle #3Local quality

3Productivity

If inductors move along the circumference heating and quenching successively, then the bearing ring can be hardened, but the end zone region cannot be sufficiently quenched leading to non-uniform hardness

Engineering Contradiction:

Improvehardening efficiencyVSAvoidhardness uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The third quenching device is pre-positioned in the end zone to be ready for operation. As the first and second inductors approach and pass through the end zone, the third quenching device activates to provide the necessary quenching action in this previously problematic region. This preliminary positioning and coordinated activation ensures uniform quenching coverage without interrupting the continuous hardening process.

Inventive Principle:

Principle #10Preliminary action

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 allows for uniform hardness across the entire circumference and contour of the bearing ring, preventing interruptions in heating and quenching, thus achieving optimal hardness without microstructure deterioration.

Implementation Method 1

each include a heating element for heating the bearing ring to be hardened

Methodology Applied

Scientific EffectInduction heating: Induction Heating

Implementation Method 2

an induction hardening system for induction hardening a bearing ring

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a quenching device for quenching the bearing ring heated by the heating element

Methodology Applied

Scientific EffectQuenching: Heat Treatment

Data Source

PatentUS12258642B2Method of induction-hardening a rolling-element bearing ring

Publication Date: 2025.03.25 AB SKF SKF PATENT DEPARTMENT

AI summary

A method of induction hardening a bearing ring includes positioning first and second inductors at a start zone on the bearing ring and a preheat inductor in an end zone on the bearing ring spaced one hundred eighty degrees from the start zone. A first traversing element moves the first inductor circumferentially from the start zone toward the end zone along a first half of the bearing ring circumference while the first inductor heats the bearing ring, and a second traversing element moves the second inductor circumferentially from the start zone toward the end zone along a second half of the bearing ring circumference while the second inductor heats the bearing ring. A third traversing element moves the preheat inductor circumferentially within the end zone so as to traverse a portion of each half of the bearing ring circumference while the preheat inductor heats the end zone.