Heat Sink Mounting Assembly for Precise PCB Cooling Alignment

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Solution Overview

Problem

Existing electronic assemblies face issues with inadequate thermal contact between the heat sink and electronic components due to misalignment, leading to poor cooling and potential component failure.

Innovation Solution

An electronic assembly design featuring an auxiliary structure with clamp and heat sink receptacles that allows for precise alignment and fixation of the heat sink relative to the cooling surface, using retaining hooks and clamps to ensure parallel alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual placement of heat sink and clamp is used, then assembly flexibility is maintained, but alignment precision deteriorates leading to tilted contact surface

Engineering Contradiction:
Improvealignment precisionVSAvoidassembly structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The auxiliary structure is prepared in advance with integrated clamp receptacle and heat sink receptacle features molded into it. The clamp and heat sink are inserted into their respective receptacles before the auxiliary structure is mounted to the circuit board, ensuring pre-alignment and preventing tilting during final assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The auxiliary structure serves as an intermediary component that mediates between the clamp/heat sink and the circuit board. It provides dedicated receptacles with retaining hooks that guide and constrain the heat sink and clamp into proper alignment, eliminating the need for complex adjustment mechanisms while ensuring precise positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If heat sink contact surface is tilted relative to cooling surface, then assembly simplicity is maintained, but thermal contact quality deteriorates

Engineering Contradiction:
Improvethermal contact qualityVSAvoidassembly ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The auxiliary structure incorporates local geometric features including retaining hooks positioned at specific locations to engage with the heat sink. These localized structural elements provide precise alignment constraints at critical points, ensuring the contact surface remains parallel to the cooling surface while maintaining overall assembly simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The heat sink is inserted into the heat sink receptacle with retaining hooks before final assembly, pre-establishing the correct orientation and parallel alignment between the contact surface and cooling surface. This preliminary positioning prevents tilting and ensures optimal thermal contact from the outset.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If thermal paste is applied to improve thermal contact, then thermal conductivity is enhanced, but assembly complexity increases and effectiveness is limited by misalignment

Engineering Contradiction:
Improvecooling effectivenessVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The auxiliary structure with its integrated receptacles and retaining hooks is designed to ensure proper alignment before thermal paste application. By pre-aligning the heat sink contact surface parallel to the cooling surface through the receptacle geometry, the need for extensive thermal paste compensation is eliminated, and assembly remains simple.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The auxiliary structure acts as an intermediary that ensures proper mechanical alignment between the heat sink and cooling surface, making thermal paste application less critical. The retaining hooks and receptacle design provide the primary alignment function, reducing reliance on thermal paste for contact quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enhances thermal contact and cooling efficiency, preventing component damage and enabling reliable operation, with potential for automated assembly.

Implementation Method 1

a heat sink (5), which is placed with a contact surface (6) on the cooling surface (4)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the auxiliary structure (9) has a heat sink receptacle (20) into which the heat sink (5) can be inserted before the auxiliary structure (9) is placed on the component side (2), and in which the heat sink (5) is held and guided

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 3

the heat sink receptacle (20) has retaining hooks (21), by means of which a movement of the heat sink (5) in the direction of the circuit board (1) is limited

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 4

a clamp (7), which engages over the heat sink (5) on its side facing away from the component (3) and is connected to the circuit board (1)

Methodology Applied
Scientific EffectMechanical compression: Compression

Data Source

PatentEP4492453B1Electronic assembly with improved mounting of a heat sink
Publication Date: 2025.09.24 SIEMENS AG
  • EP4492453B1 patent drawingFigure 1~2
  • EP4492453B1 patent drawingFigure 3~4
  • EP4492453B1 patent drawingFigure 5

AI summary

An electronic assembly comprises a printed circuit board (1) with a component side (2). An electronic component (3) is arranged on the component side (2) and has a cooling surface (4) on its side facing away from the printed circuit board (1), extending parallel to the printed circuit board (1). The assembly includes a heat sink (5) which is mounted on the cooling surface (4) of the electronic component (3) via a contact surface (6). The assembly includes a clamp (7) that extends over the heat sink (5) on its side facing away from the component (3) and is connected to the printed circuit board (1). The assembly includes an auxiliary structure (9) made of an electrically insulating material, which is mounted on the component side (2). The auxiliary structure (9) has a clamp receptacle (10) for the clamp (7), into which the clamp (7) can be inserted before the auxiliary structure (9) is mounted on the component side (2).The auxiliary structure (9) has a heat sink receptacle (20) into which the heat sink (5) can be inserted before the auxiliary structure (9) is placed on the component side (2), and in which the heat sink (5) is held and guided. The heat sink receptacle (20) has retaining hooks (21) by means of which movement of the heat sink (5) towards the printed circuit board (1) is limited. After the clamp (7) is connected to the printed circuit board (1), either the heat sink (5) is spaced apart from the retaining hooks (21), or the heat sink (5) is pressed against the retaining hooks (21) by the clamp (7), and the auxiliary structure (9) is bent by this pressure.