Electric Vehicle Motion Sensor Vibration Decoupling

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Solution Overview

Problem

Existing motor vehicle sensor systems face challenges in reliably detecting changes in vehicle attitude or motion due to vibrations and noise interference from the main circuit board, leading to potential erroneous deployment of safety and reaction systems.

Innovation Solution

A motor vehicle sensor assembly featuring a daughter board assembly with sensors, electrically connected to a circuit board via a flexible connector, and mounted to a housing with a receiving feature that decouples the daughter board from the circuit board, using a retention feature for interference fit and damping compound to reduce vibrations, allowing accurate detection of vehicle motion and attitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensing assembly is mechanically coupled to the main circuit board, then electrical connection and data transmission are achieved, but vibrations and noise from the circuit board interfere with sensor readings

Engineering Contradiction:
Improvesensor data transmission reliabilityVSAvoidvibration and noise interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the circuit board into separate functional sections: a main circuit board for power and control, and a daughter board for sensor elements. This segmentation allows the sensor board to be physically isolated from vibration sources on the main board, reducing noise interference while maintaining electrical connectivity through controlled interfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensing assembly is extracted from the main circuit board and placed on a separate daughter board. This extraction removes the sensors from the harmful vibrational environment of the main board while preserving the necessary electrical connection through the flexible connector and connector assembly.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If the sensor assembly is isolated from the circuit board to reduce vibrations, then measurement accuracy improves, but electrical connection complexity increases

Engineering Contradiction:
Improvevehicle motion detection accuracyVSAvoidelectrical connection structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A flexible connector is used to electrically connect the daughter board to the main circuit board. This flexible printed circuit board provides reliable electrical connectivity while allowing physical separation and isolation of the sensor elements from vibration sources, maintaining measurement precision without excessive complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces an intermediary connector assembly that includes a connector housing, mounting features, and electrical contacts. This intermediary structure simplifies the connection between the separated main board and daughter board, providing a standardized interface that reduces overall system complexity despite the physical separation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If damping compound is added to reduce vibrations, then sensor reliability improves, but manufacturing complexity increases

Engineering Contradiction:
Improvesensor data transmission reliabilityVSAvoidassembly manufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Damping compound is applied to the housing or mounting surfaces before assembling the sensor components. This pre-applied cushioning material provides vibration isolation and noise reduction, improving sensor reliability while maintaining a relatively simple manufacturing process through pre-preparation of damping elements.

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

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 enhances the reliability of sensor data transmission, reducing the likelihood of erroneous safety system deployments by effectively decoupling the daughter board from the main circuit board vibrations, thereby improving the accuracy of vehicle motion and attitude detection.

Implementation Method 1

The flexible connector isolates the daughter board from the circuit board

Methodology Applied
Scientific EffectVibration isolation: Damping

Implementation Method 2

The retention feature includes an element that causes an interference fit between the daughter board assembly and the housing

Methodology Applied
Scientific EffectInterference fit: Friction

Implementation Method 3

damping compound to reduce vibrations

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP2099654B1Electric vehicle motion sensor
Publication Date: 2016.02.17 AUTOLIV ASP INC
  • EP2099654B1 patent drawingFigure 1
  • EP2099654B1 patent drawingFigure 2
  • EP2099654B1 patent drawingFigure 3

AI summary

A motor vehicle motion sensor assembly includes a daughter board assembly having an alignment feature, a circuit board having electronic components, and a housing element having a receiving feature for receiving the daughter board assembly. The circuit board is electrically connected with the daughter board assembly by a flexible electrical connector. The circuit board is further connected with an external circuit connector. The alignment feature of the daughter board assembly is adapted to engage the receiving feature of the housing element.