Sensor Device Vibration Damping via Hardness Gradient

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Solution Overview

Problem

Existing sensor devices face impaired detection accuracy and reliability due to external vibrations and shocks being transmitted to the sensor module through the housing, especially in high-vibration environments.

Innovation Solution

The sensor device employs a fastening means that is glued to both the sensor module and the housing, with a potting compound having a higher hardness than the fastening means but lower than the housing, acting as a vibration damper to decouple the sensor module from the housing, and is coated with a protective layer to prevent moisture-related issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor module is rigidly mounted to the housing, then the sensor module is securely fixed in the housing, but external vibrations and shocks are transmitted to the sensor module, impairing detection accuracy and reliability

Engineering Contradiction:
Improvedetection reliabilityVSAvoidvibration transmission
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a fastening means as an intermediary element between the sensor module and the housing. This fastening means has different mechanical properties than both the sensor module and the housing, allowing it to decouple vibration transmission while maintaining secure mechanical attachment. The intermediary layer absorbs and dampens vibrational energy, preventing direct transmission to the sensitive sensor element.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the mechanical parameters of the mounting system by selecting a fastening means with specific hardness and damping characteristics. By adjusting the hardness, elasticity, and damping coefficients of the fastening means, the system transforms from a rigid connection that transmits vibrations to a compliant connection that isolates the sensor module from vibrational harmful factors.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a soft fastening means is used to dampen vibrations, then vibration isolation is improved, but the fastening strength may be insufficient to securely hold the sensor module in the housing

Engineering Contradiction:
Improvevibration dampingVSAvoidfastening strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The fastening means is designed as a composite structure or composite material system that combines materials with different mechanical properties. This allows the fastening means to simultaneously provide adequate mechanical strength for secure mounting and sufficient damping characteristics for vibration isolation. The composite nature enables optimization of both contradictory requirements within a single component.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the housing is completely filled with potting compound, then the sensor module is well protected from moisture, but the sensor module may be subjected to stress from the rigid housing structure

Engineering Contradiction:
Improvemoisture protectionVSAvoidmechanical stress on sensor module
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The patent changes the mechanical parameters of the housing structure by introducing compliance elements and designing the housing with stress-relief features. The housing is designed to accommodate thermal and mechanical expansion without transmitting excessive stress to the sensor module, while still providing complete moisture protection through the potting compound filling.

Inventive Principle:
Principle #35Parameter changes

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 configuration ensures reliable detection of physical quantities by isolating the sensor module from vibrations and moisture, enhancing detection accuracy and reliability, especially in high-vibration environments.

Implementation Method 1

the casting compound with which the housing is filled and which encloses the sensor module has a hardness in the hardened state that is greater than the hardness of the at least one fastening means and less than the hardness of the housing... the casting compound acts as a vibration damper for the sensor module and decouples the sensor module from the housing in terms of vibrations

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 2

The at least one fastening means is preferably glued both to the sensor module and to the housing in order to provide reliable fastening of the sensor module during assembly of the sensor device

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3857172B1Sensor device
Publication Date: 2023.07.05 FRABA
  • EP3857172B1 patent drawingFigure 1
  • EP3857172B1 patent drawingFigure 2~3
  • EP3857172B1 patent drawingFigure 4~5

AI summary

The invention relates to a sensor device (10) for capturing a physical variable, having - a housing (12), - a sensor module (28) which is arranged in the housing (12) and has • a module board (30) and • at least one motion-sensitive sensor element (32) which is arranged on the module board (30), - and a potting compound (38) which at least partially fills the housing (12) and surrounds the sensor module (28). As a result of the fact that at least one fastening means (36a-c) is provided and is used to fasten the sensor module (28) to the housing (12) and the potting compound (38) in the cured state has a hardness which is greater than the hardness of the at least one fastening means (36a-c) and is less than the hardness of the housing (12), it is possible to capture the physical variable in a reliable and interference-free manner, in particular even in high-vibration environments.