Caulked Heat Pipe Structure With Gap-Filling Metal Interface

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Solution Overview

Problem

Existing heat pipe structures connected to base blocks via caulking methods often suffer from reduced heat transferability and fixing stability due to air gaps formed between the base block and the heat pipe, which limits the effectiveness of heat transfer and the reliability of the connection.

Innovation Solution

A heat pipe structure where a first metal part with a melting point between 130°C and 400°C is formed between the recessed part of the base block and the heat pipe's container part, filling air gaps and enhancing the connection's stability, while a second metal part with a higher melting point provides additional functionality and corrosion resistance, and a third metal part may be used to further improve heat transferability by filling gaps around bent parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If caulking method is used to connect heat pipe to base block, then operation complexity is reduced and cost is lowered, but air gaps are formed reducing heat transferability

Engineering Contradiction:
Improveoperation complexityVSAvoidheat transferability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A solder layer is introduced as an intermediary substance between the heat pipe and base block. This solder layer fills the air gaps that form during caulking connection, providing a thermal conduit that maintains excellent heat transferability while allowing the simpler caulking method to be used for fixation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The connection structure becomes a composite system combining three materials: the base block material, the heat pipe material, and the solder material. This composite approach leverages the mechanical fixation capability of caulking while using solder to bridge thermal gaps, achieving both ease of manufacture and reliable heat transfer.

Inventive Principle:
Principle #40Composite materials

2Reliability

If soldering method is used to connect heat pipe to base block, then heat transferability is improved, but operation complexity increases and cost increases

Engineering Contradiction:
Improveheat transferabilityVSAvoidoperation complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of using complete soldering for both fixation and heat transfer, the invention applies soldering partially - only for filling the connection gap and ensuring heat transferability. The primary fixation function is handled by the simpler caulking method, reducing overall operation complexity while maintaining thermal performance.

Inventive Principle:
Principle #16Partial or excessive action

3Ease of manufacture

If caulking method is used to connect heat pipe to base block, then cost is reduced, but fixing stability is reduced due to air gaps

Engineering Contradiction:
ImprovecostVSAvoidfixing stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The solder layer serves as a mediator that fills voids and air gaps in the caulking connection interface. This improves the mechanical interlocking between heat pipe and base block, enhancing fixing stability without requiring expensive plating films or complex multi-step processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If plating film is formed on base block before soldering, then heat transferability is improved, but cost increases

Engineering Contradiction:
Improveheat transferabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention applies soldering partially - only in the specific connection region where the heat pipe contacts the base block, rather than forming plating films on entire surfaces. This localized approach achieves necessary heat transferability while significantly reducing material costs compared to comprehensive plating.

Inventive Principle:
Principle #16Partial or excessive 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

The solution significantly improves heat transferability and fixing stability between the heat pipe and the base block, preventing damage from heat generation temperatures and enhancing corrosion resistance, thus enhancing the overall cooling performance and reliability of the heat pipe structure.

Implementation Method 1

a first metal part containing first metal having a melting point equal to or higher than 130°C and equal to or lower than 400°C and/or a first metal alloy having a melting point equal to or higher than 130°C and equal to or lower than 400°C is formed between the recessed part and an outer surface of the container part

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The heat pipe transports heat received from the heat generating body, which is a cooling target, via the base block using latent heat due to a phase change of this working fluid

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 3

The heat pipe transports heat received from the heat generating body, which is a cooling target, via the base block using latent heat due to a phase change of this working fluid

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Data Source

PatentEP3909711B1Heat pipe structure, heat sink, method for producing heat pipe structure, and method for producing heat sink
Publication Date: 2025.03.26 FURUKAWA ELECTRIC CO LTD
  • EP3909711B1 patent drawingFigure 1
  • EP3909711B1 patent drawingFigure 2
  • EP3909711B1 patent drawingFigure 3~4

AI summary

An object of the present invention is to provide a heat pipe structure excellent in heat transferability from a base block to a heat pipe and excellent in fixing stability of the heat pipe to the base block even if the heat pipe is thermally connected to the base block using caulking means and a heat sink including the heat pipe structure. A heat pipe structure includes a base block including a rear surface part thermally connectable to a heat generating body and a heat pipe including a heat receiving tubular portion fixed to a front surface part of the base block and disposed along an in-plane direction of the base block. The base block has a longitudinal direction and a width direction and includes a recessed part in which the heat receiving tubular portion is accommodated, and a container part of the heat pipe is caulked and fixed in the recessed part and a first metal part containing first metal having a melting point equal to or higher than 130°C and equal to or lower than 400°C and/or a first metal alloy having a melting point equal to or higher than 130°C and equal to or lower than 400°C is formed between the recessed part and an outer surface of the container part.