Helical Gear Quenching Distortion Control via Dynamic Support Decoupling

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Solution Overview

Problem

Existing methods for producing heat-treated workpieces, such as double-row helical gears, face challenges in minimizing component distortion and achieving comprehensive hardening with narrow shape tolerances, which are not reliably reproducible.

Innovation Solution

A device and method involving a tool set, loading device, and control device to support workpieces during quenching, where a support tool is decoupled from the workpiece after the martensite transformation, allowing for reduced distortion and precise control of the quenching process, including the use of a mandrel tailored to the workpiece's geometry and thermal expansion state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the support tool is maintained in the workpiece until the target quenching temperature is reached, then the workpiece is continuously supported against deformation, but the workpiece distortion increases due to thermal expansion and structural transformation forces

Engineering Contradiction:
Improveworkpiece shape accuracyVSAvoidworkpiece distortion
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The support tool is introduced into the heated workpiece before quenching begins, establishing dimensional stability and preventing distortion during the critical martensite transformation phase. The support tool is removed at an intermediate temperature before complete cooling, avoiding the harmful effects of prolonged constraint during thermal contraction while maintaining precision during the most critical transformation period.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The support process is made dynamic by removing the support tool at a specific intermediate temperature during the quenching process, rather than maintaining static support until complete cooling. This dynamic approach allows the workpiece to be supported when most needed (during martensite transformation) while avoiding distortion caused by thermal expansion and contraction forces.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the quenching process is completed to room temperature with continuous support, then comprehensive hardening is achieved, but the pressing force required to remove the support tool becomes excessive

Engineering Contradiction:
Improvehardening completenessVSAvoidpressing force for support tool removal
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The support tool is removed at an intermediate temperature during the quenching process, before complete cooling to room temperature. This preliminary removal avoids the excessive pressing forces that would be required if removal were attempted after complete cooling, when thermal contraction has created a tight interference fit. The quenching process is completed to room temperature with the workpiece already free of the support tool.

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 significantly reduces workpiece distortion and achieves more comprehensive hardening with narrow shape tolerances, ensuring reliable reproducibility and precise control throughout the quenching process.

Implementation Method 1

the initially thermally expanded workpiece shrinks still enables it to be pressed out at room temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The workpiece secured in this way by the mandrel and the axial clamping against deformation in the hardening press is quenched by applying a cooling medium to the workpiece to achieve a high heat transfer rate

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

support a workpiece made of a steel material in the phase of martensite transformation

Methodology Applied
Scientific EffectMartensite transformation: Phase Change

Data Source

PatentEP4261292A1Device and method for producing heat-treated workpieces, in particular helical gear wheels, and control device therefor
Publication Date: 2023.10.18 AEROSPACE TRANSMISSION TECH
  • EP4261292A1 patent drawingFigure 1a
  • EP4261292A1 patent drawingFigure 1b
  • EP4261292A1 patent drawingFigure 2~3

AI summary

The invention relates to a device for hardening a workpiece that has been heated initially, using a tool set, for forming a workpiece receiving chamber for receiving the workpiece, a contacting device for bringing the workpiece into contact with a quenching medium in the workpiece receiving chamber, a support tool for providing a wall to support the workpiece against deformation, a decoupling mechanism for decoupling the support tool and the workpiece, and a control device for controlling the decoupling mechanism and the contacting device, wherein the control device is configured such thatthat, after a first phase of applying the quenching medium to the workpiece, the support tool is decoupled from the workpiece, and in a second phase of applying the quenching medium to a wall area of ​​the workpiece released by the support tool. The invention further comprises the control device itself, a tool set, and a method executed according to the control device.