Bearing Heater Induction Cycle Control

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Solution Overview

Problem

Existing induction heating methods for rolling element bearings require lengthy heating times, and increasing power to reduce this time risks damaging the bearing due to uneven thermal expansion between the inner and outer rings.

Innovation Solution

A method using a sequential heating cycle with a high-power first portion to rapidly raise the inner ring temperature and a lower-power second portion to balance the temperature difference between the rings, controlled by temperature probes and a circuit to prevent excessive thermal expansion, optimizing the overall heating time while minimizing risk of damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If induction power of the heater is increased to reduce heating time, then heating time is reduced, but the risk of damaging the bearing due to uneven thermal expansion increases

Engineering Contradiction:
Improveheating timeVSAvoiddamage risk from uneven thermal expansion
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The heating cycle is divided into multiple segments with different power levels. The first segment uses high power to rapidly heat the inner ring, followed by a second segment with reduced power to allow the outer ring to catch up thermally, thereby reducing overall heating time while preventing excessive temperature differences that could damage the bearing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The heating process uses periodic action by alternating between high-power and low-power phases. The controller switches between these phases based on temperature feedback, creating a periodic heating pattern that efficiently reduces heating time while maintaining temperature differences within safe limits to prevent bearing damage

Inventive Principle:
Principle #19Periodic action

2Productivity

If high power is used throughout the heating cycle, then heating time is minimized, but the temperature difference between inner and outer rings becomes excessive causing bearing damage

Engineering Contradiction:
Improveheating efficiencyVSAvoidbearing integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The heating system dynamically adjusts power levels based on real-time temperature conditions. The controller monitors temperatures of both inner and outer rings and dynamically switches between high-power and low-power phases, optimizing heating efficiency while maintaining bearing integrity through adaptive power control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback control by continuously monitoring the temperatures of the inner and outer rings and using this information to control the switching between heating phases. This feedback mechanism ensures that the temperature difference remains within safe limits while maximizing heating efficiency, thus maintaining bearing reliability

Inventive Principle:
Principle #23Feedback

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 significantly reduces the overall heating time while ensuring the safety of the bearing by managing the temperature difference between the inner and outer rings, preventing damage and optimizing the heating process.

Implementation Method 1

using a first portion of a heating cycle to rapidly raise the temperature of an inner ring of the rolling bearing

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 2

heating a rolling element bearing using an induction heater which has at least first and second induction coils

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

Thermal expansion of such rolling bearings induced by induction heating is used, for example, to facilitate the mounting of the bearing on a shaft

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2728965B1Bearing heater
Publication Date: 2017.08.16 AB SKF SKF PATENT DEPARTMENT
  • EP2728965B1 patent drawingFigure 1~2

AI summary

Improved induction heating of a rolling element bearing without the risk of damaging or blocking the bearing is achieved by controlling the heating cycle as a function of the temperature difference between the inner (4) and outer (5) bearing rings.