Hold-Down Device for Reliable PCB Connections
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrical devices in motor vehicles face reliability issues due to high temperatures and temperature fluctuations, which cause soldered connections on printed circuit boards to melt and break, leading to increased costs when using ceramic substrates and specialized materials.
Innovation Solution
A hold-down device made of temperature-resistant materials, such as silicone foam, is used to press electrical components perpendicularly against a carrier plate, ensuring reliable connections even at high temperatures and fluctuations, allowing for the use of conventional components and solder connections, thus reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a printed circuit board is used as the carrier plate with soldered connections, then production costs are reduced and ease of manufacture is improved, but reliability deteriorates due to solder connections melting and breaking under high temperatures and temperature fluctuations
Solution Approach 1:
The patent introduces a hold-down device as an intermediary component between the housing and the electrical component. This hold-down device applies continuous mechanical pressure to press the component's connection contacts against the conductive layer on the carrier plate, ensuring reliable electrical connection despite thermal expansion differences. This mediator compensates for the weakness of soldered connections under temperature fluctuations without requiring expensive ceramic substrates.
2Reliability
If a ceramic substrate is used as the carrier plate with conductive adhesive, then reliability is improved by eliminating temperature-related connection failures, but production costs increase due to material costs and specialized component requirements
Solution Approach 1:
The patent changes the parameter of connection method from permanent bonding (solder or conductive adhesive) to mechanical pressing with continuous force. The hold-down device maintains constant pressure on the electrical component, ensuring stable electrical contact without relying on the thermal stability of bonding materials. This parameter change allows the use of standard printed circuit boards and conventional components while achieving reliability comparable to ceramic substrates.
3Ease of manufacture
If conventional components with soldered connections are used, then production costs are reduced, but the connections fail under high temperatures and vibrations in motor vehicle environments
Solution Approach 1:
The hold-down device applies preliminary counteracting force to prevent the harmful effects of thermal expansion and vibration. By continuously pressing the electrical component against the carrier plate, it compensates for the loosening effect of temperature fluctuations and vibrations before they can cause connection failure. This preliminary anti-action allows conventional components to withstand motor vehicle operating conditions.
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 ensures reliable electrical connections and fixation at high temperatures and vibrations, preventing component detachment and maintaining functionality despite thermal expansion differences, while significantly lowering production costs by using conventional components and materials.
Implementation Method 1
A hold-down device (30) is supported on the housing component (12) and presses the at least one component (15, 17, 19, 21, 23, 25) mounted on the carrier plate (10) under pressure essentially perpendicularly against the carrier plate (10)
Implementation Method 2
the hold-down device has a layer made of a foam with resilient properties at least in sections. The layer can be formed from a silicone foam, for example, which on the one hand has the required temperature resistance and on the other hand has the necessary resilient properties in order to be able to exert sufficient pressure on the components
Implementation Method 3
The disadvantage here is that the soldered connections can melt and break under the conditions of use with the high temperatures and temperature fluctuations due to the different thermal expansion coefficients of the circuit board material and the components
Data Source
Figure 1~3
AI summary
The equipment (1) has a structured, electrically conductive layer (11) applied on a carrier plate (10) i.e. printed circuit board, where electrical elements (15, 17, 19, 21, 23, 25) are connected with the layer by using a connecting unit i.e. solder. A housing component (12) is arranged fixedly relative to the plate, where the component surrounds the elements. A press pad (30) is reinforced at the component, where the pad presses the elements perpendicularly against the plate under pressure. The pad is made of a temperature-resistant material, and the layer is made of silicone foam.