Vehicle Control Unit Adhesive Bond Quality Monitoring
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Solution Overview
Problem
Control units with encapsulated printed circuit boards face issues with reduced adhesive bonds between the encapsulation and the printed circuit board, leading to potential corrosion and unexpected failures due to external media ingress, necessitating early detection during production.
Innovation Solution
Incorporating conductor loops on the printed circuit board, with one loop between the edge and another loop near electronic components, and measuring insulation resistance between these loops or with respect to an electrically conductive medium to assess the adhesive bond quality, allowing for early detection of reduced adhesive bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adhesive bond between the printed circuit board and the encapsulation weakens, then a gap can form allowing corrosive media to enter, but the control unit structure remains unchanged
Solution Approach 1:
The patent applies preliminary action by measuring the insulation resistance between conductor loops during the production process, before the control unit is shipped. This early detection allows identification of reduced adhesive bonds before corrosive media can cause damage, enabling preventive quality control.
Solution Approach 2:
The patent introduces an intermediary measurement method using insulation resistance as an indirect indicator of adhesive bond quality. Instead of directly measuring adhesive strength, the insulation resistance between conductor loops serves as a mediator to detect gaps formed by weakened adhesive bonds.
2Measurement precision
If insulation resistance measurement is performed between conductor loops, then reduced adhesive bonds can be detected early, but additional measurement infrastructure is required
Solution Approach 1:
The patent extracts the detection function by separating the quality assessment from the control unit's operational function. The insulation resistance measurement is performed independently using external test equipment, allowing the control unit itself to remain simple while enabling precise quality detection through the conductor loops integrated into the PCB.
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
Enables effective quality monitoring during production, preventing faulty units with reduced adhesive bonds from being shipped by identifying insulation resistance changes, thus ensuring the integrity of the control units.
Implementation Method 1
An insulation resistance between the conductor loops can be measured to detect the tightness or the adhesive bond between the encapsulation and the printed circuit board
Data Source
AI summary
A control unit for a motor vehicle is provided. The control unit includes a printed circuit board having a first side and an edge. The first side is delimited by the edge. At least one electronic component is arranged on the first side of the printed circuit board and is electrically conductively connected to the printed circuit board. At least one first conductor loop is arranged on the first side of the printed circuit board and at least one second conductor loop is arranged at a distance from the first conductor loop. The first conductor loop is arranged between the edge and the second conductor loop, and the second conductor loop is arranged between the first conductor loop and the at least one electronic component. An encapsulation surrounds at least the first side, the at least one electronic component, the first conductor loop and the second conductor loop.