Elastic PCB Clamping Elements for Thermal Expansion Compensation

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Solution Overview

Problem

Existing methods for fixing printed circuit boards in housings require high tolerance and can cause mechanical stress due to thermal expansion, leading to potential bending and reduced service life, and often involve adhesive materials that may damage the circuit board.

Innovation Solution

A printed circuit board holding device with elastic clamping elements that absorb mechanical forces and compensate for thermal expansion, allowing for secure, non-adhesive fixation and reduced mechanical stress, featuring elastic sections in the clamping elements to adapt to tolerance deviations and distribute forces evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If high tolerance requirements are imposed on PCB and housing for secure clamping, then clamping stability is improved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improveclamping stabilityVSAvoidtolerance requirements
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The clamping element's material parameters are specifically optimized to provide elasticity and damping properties. The elastic section is designed with specific modulus of elasticity and geometric dimensions to compensate for tolerance deviations, allowing the system to maintain stable clamping without requiring high manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The clamping element is designed as a composite structure with a rigid clamping section and a flexible elastic section. This composite design allows the rigid part to provide structural support while the elastic part absorbs tolerance variations and mechanical stresses, achieving stable clamping without high tolerance requirements.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If direct clamping of PCB by housing is used to simplify structure, then device complexity is reduced, but mechanical stress on PCB increases due to thermal expansion

Engineering Contradiction:
Improvestructure simplicityVSAvoidmechanical stress from thermal expansion
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The elastic section of the clamping element acts as a flexible component that can deform elastically in response to thermal expansion and contraction of the PCB. This flexibility allows the system to maintain simple structure while protecting the PCB from mechanical stress caused by thermal effects.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The elastic section is pre-designed to provide cushioning effect against mechanical stresses. By incorporating this elastic element beforehand, the system prepares for thermal expansion stresses, allowing the PCB to expand and contract without experiencing damaging mechanical forces.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If elastic sections are introduced in clamping elements to compensate tolerances, then tolerance requirements are reduced, but device complexity increases

Engineering Contradiction:
Improvetolerance requirementsVSAvoidclamping element structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The clamping element is segmented into distinct functional sections: a rigid clamping section for structural support and positioning, and a flexible elastic section for tolerance compensation. This segmentation allows each part to be optimized for its specific function while keeping the overall design relatively simple and manufacturable.

Inventive Principle:
Principle #1Segmentation

4Stability of the object's composition

If adhesive materials are used to fix PCB to housing, then fixation stability is improved, but risk of PCB damage during removal increases

Engineering Contradiction:
Improvefixation stabilityVSAvoidPCB damage risk
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention replaces the chemical bonding mechanism of adhesives with a mechanical clamping system. The elastic clamping elements provide stable fixation through mechanical force while allowing for stress-free removal, eliminating the harmful effects of adhesive residue and PCB damage associated with chemical bonding methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 provides a stable and durable fixation of printed circuit boards across a wide temperature range, reducing mechanical stress and increasing the service life by absorbing vibrations and tolerance deviations, while avoiding the use of adhesives that could damage the circuit board.

Implementation Method 1

The elastic section is designed to elastically absorb mechanical forces, in particular those perpendicular to the surface of the printed circuit board

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the elasticity of the clamping element dampens mechanical vibrations and oscillations

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 3

the clamping elements can adapt to the installation conditions... when the printed circuit board expands perpendicular to its surface, for example, due to heat

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2315513B1Tolerance-free circuit board clamp
Publication Date: 2020.04.15 ROBERT BOSCH GMBH
  • EP2315513B1 patent drawingFigure 1~2d
  • EP2315513B1 patent drawingFigure 3
  • EP2315513B1 patent drawingFigure 4~6

AI summary

The device has clamping elements (8, 9) made electric conductive material for clamping a printed circuit board (6) between an upper side (11) and a lower side (13), where the clamping elements include rod shaped pins that elastically accommodate mechanically forces and are provided perpendicular to surface areas of the upper and lower sides of the printed circuit board, respectively. The elastic sections are arranged on a contact point to the printed circuit board, and the clamping elements include base bodies that are connected with the elastic sections.