Heat-Conducting Element for Length Measuring Device Thermal Management

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Solution Overview

Problem

Length measuring devices face measurement inaccuracies due to temperature changes caused by electrical components, which are not adequately addressed by existing heat dissipation methods, and require high resolution and accuracy while integrating more electrical components, leading to increased heat generation and scale heating.

Innovation Solution

A heat conduction path is created between the heat-generating sensor chip and the housing using a heat-conducting element with low thermal resistance, allowing efficient heat transfer without impeding the scanning unit's movement, utilizing a gap for effective heat transfer while maintaining precise guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If more electrical components are integrated in the scanning unit to achieve compact design and high resolution, then device functionality and measurement precision are improved, but heat generation increases causing scale heating and measurement inaccuracies

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidscale temperature
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The harmful heat generated by the sensor chip is extracted and separated from the scale by introducing a heat-conducting element that creates a dedicated heat conduction path to the housing, removing the thermal disturbance from the measurement area

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A heat-conducting element is introduced as an intermediary component between the sensor chip and the housing to facilitate heat transfer away from the scale, acting as a thermal conduit that protects the measurement system from heat generation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If a heat conduction path is created using a heat-conducting element between the sensor chip and housing, then heat dissipation is improved, but the scanning unit's movement may be impeded

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidscanning unit movement
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The heat-conducting element is designed with spatially varying properties - it provides efficient thermal conduction in the heat transfer direction while maintaining minimal interference with the mechanical movement of the scanning unit, achieving different functional qualities in different spatial dimensions

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The heat-conducting element serves as a mediator that transfers heat energy without significantly interfering with the mechanical motion of the scanning unit, decoupling the thermal management function from the mechanical guidance function

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If the scanning distance is reduced to less than 100 μm to achieve high resolution, then measurement precision is improved, but the scanning unit is more sensitive to temperature changes and heat effects

Engineering Contradiction:
ImproveresolutionVSAvoidmeasurement stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The heat affecting the scanning unit is extracted and redirected to the housing through the heat-conducting element, removing the thermal instability that would otherwise affect the high-resolution measurement with small scanning distance

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The heat-conducting element provides preliminary thermal protection by actively managing heat flow before it can affect the scanning unit and scale, preventing temperature-induced measurement errors before they occur

Inventive Principle:
Principle #9Preliminary anti-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 solution enables a compact, high-accuracy length measuring device with reproducible position measurements by effectively dissipating heat from the sensor chip to the housing, reducing measurement errors caused by temperature changes and ensuring precise guidance.

Implementation Method 1

A heat conduction path is created between a heat-generating sensor chip of the scanning unit and the housing of the length measuring device

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2344847B1Length measuring device
Publication Date: 2018.05.16 DR JOHANNES HEIDENHAIN GMBH
  • EP2344847B1 patent drawingFigure 1
  • EP2344847B1 patent drawingFigure 2~3

AI summary

The invention relates to a length measuring device comprising a scale (20) arranged inside a housing (22) and a sensor chip (13) of a scanning unit (10) that scans the scale (20). The heat generated by the sensor chip (13) of the scanning unit (10) is specifically directed in the direction of the housing (22). For this purpose, a thermally conductive element (19) is coupled to the sensor chip (13). Said thermally conductive element leads to the housing (22) and transfers the heat to the housing (22) across a small gap (L).