Pressing Elements for PCB Thermal Contact

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Solution Overview

Problem

Existing electrical devices face challenges in securely and efficiently connecting printed circuit boards to heat sinks, particularly in compensating for tolerance variations and ensuring a reliable thermal connection while maintaining a sealed and cost-effective assembly process.

Innovation Solution

The use of longitudinally displaceable pressure elements, such as pressure bolts or pins, which are designed to press the printed circuit board against the heat sink, allowing for variable force application and compensation of tolerance variations, while also forming a fixing mechanism and providing a visual indication of correct installation through signal colors. These pressure elements are made from materials with different moduli of elasticity and can be produced using injection molding techniques to ensure cost-effectiveness and rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fixed-length pressure bolts are formed on the housing cover, then the housing cover structure is simple, but the printed circuit board cannot be subjected to variable force and tolerance compensation is limited

Engineering Contradiction:
Improvevariable force applicationVSAvoidpressure element structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pressure element is designed as a longitudinally displaceable component within the housing cover, allowing it to dynamically adjust its position and apply variable force to the printed circuit board. This dynamic capability enables tolerance compensation while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The pressure element can change its longitudinal position parameter to compensate for tolerance variations in the printed circuit board assembly. By adjusting its displacement parameter, the system achieves adaptability without requiring complex mechanical structures.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the housing cover is pressed onto another housing part, then the housing assembly is completed, but the housing cover becomes loaded and may be damaged

Engineering Contradiction:
Improveassembly efficiencyVSAvoidhousing cover durability
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The pressing function is segmented from the housing cover structure. The pressure element, which is displaceably mounted in the housing cover, performs the pressing operation on the printed circuit board independently. This allows the housing cover to be assembled onto another housing part without bearing the full pressing load, protecting it from damage.

Inventive Principle:
Principle #1Segmentation

3Reliability

If multiple pressure elements are used to press the printed circuit board, then secure thermal connection is achieved, but the assembly process becomes more complex

Engineering Contradiction:
Improvethermal connection reliabilityVSAvoidpressure element arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each pressure element serves multiple functions: it applies pressing force for thermal connection, compensates for tolerance variations, and can be adjusted during assembly. This multi-functionality reduces the need for additional specialized components, maintaining assembly simplicity while ensuring reliable thermal contact.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If the pressure element remains in the displacement position pressed into the cavity, then it forms a fixing means, but the assembly disassembly becomes difficult

Engineering Contradiction:
Improvefixing capabilityVSAvoidassembly disassembly
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The pressure element is designed to automatically form a fixing means when pressed into the cavity, utilizing its own displacement capability to create the fixation. This self-service mechanism provides reliable fixing without requiring additional locking components or complex assembly procedures, and allows for relatively easy disassembly by reversing the pressing action.

Inventive Principle:
Principle #25Self-service

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 ensures a secure, thermally conductive connection between the printed circuit board and heat sink, compensates for tolerance variations, and maintains a sealed assembly, reducing the risk of foreign particles entering the housing and improving the assembly process's reliability and cost-effectiveness.

Implementation Method 1

The pressure element is designed to be pushed into the cavity and to press at least indirectly or directly against the printed circuit board and thus to press the printed circuit board against the heat sink

Methodology Applied
Scientific EffectMechanical Force: Force

Implementation Method 2

The printed circuit board is preferably connected to the heat sink in a thermally conductive manner

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Data Source

PatentEP3508043B1Electric device with a housing with pressing elements
Publication Date: 2020.09.09 ROBERT BOSCH GMBH
  • EP3508043B1 patent drawingFigure 1
  • EP3508043B1 patent drawingFigure 2
  • EP3508043B1 patent drawingFigure 3~4

AI summary

The invention relates to an electric device. The electric device has a housing, at least one printed circuit board, and at least one heat sink. The housing encloses a cavity, and the printed circuit board is received in the cavity. The printed circuit board is connected to the heat sink so as to conduct heat. According to the invention, the housing has a housing cover, and the housing cover has at least one, two, or three pressing elements, in particular pressing bolts or pressing pins, which are mounted in a movable manner along the longitudinal axis transversely to an areal extension of the housing cover. The pressing element is designed to be inserted into the cavity and to be pressed against the printed circuit board directly or at least indirectly and thus press the printed circuit board against the heat sink.