Pressure Detection Device Noise Shielding via Nested Insulated Housings

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Solution Overview

Problem

Noise interference from outside sources superposes onto the output of pressure detection devices, leading to increased errors in pressure measurement.

Innovation Solution

A pressure detection device with a detection element, a first housing with conductivity, a second housing with higher conductivity than the first, and an insulating member between them, along with a processing circuit and a DC suppressing part to reduce noise interference. The device includes a deformation member and an insulating transmission member to transmit pressure, and a fixing member to secure the housings while maintaining electrical insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the detection element is exposed to the outside environment for pressure detection, then pressure measurement function is achieved, but noise from outside enters and superposes on the output signal

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidexternal noise interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent employs a nested housing structure where an inner housing containing the detection element is placed inside an outer housing. The inner housing is electrically insulated from the outer housing through insulating members, creating a nested configuration that physically isolates the detection element from external noise sources while maintaining pressure detection capability.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Insulating members are introduced as intermediary elements between the inner housing and outer housing. These insulating members prevent direct electrical contact between the two housings, thereby blocking the transmission of external noise to the detection element while allowing the pressure detection function to operate normally.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If electrical insulation is added between housings to reduce noise, then noise suppression is improved, but device complexity increases

Engineering Contradiction:
Improveexternal noise interferenceVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The insulating members serve multiple functions simultaneously: they provide electrical insulation between the inner and outer housings to block noise, acts as mechanical support structures, and facilitate the assembly process. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the insulation function with the housing structure itself by making the inner housing and outer housing integral parts of the device, with insulating members positioned at specific locations where they perform both structural and electrical insulation roles, rather than adding separate insulation layers throughout.

Inventive Principle:
Principle #5Merging (Combining)

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

Effectively suppresses external noise interference, reducing errors in pressure measurement and enhancing the accuracy of the output from the detection element.

Implementation Method 1

a piezoelectric element disposed on a rear end side of the diaphragm in the housing to detect a pressure acting via the diaphragm

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an insulating member that has an insulating property and is disposed between the first housing and the second housing to electrically insulate the first housing and the second housing

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP3421961B1Pressure detection device and pressure detection system
Publication Date: 2022.07.27 CITIZEN FINEDEVICE CO LTD
  • EP3421961B1 patent drawingFigure 1
  • EP3421961B1 patent drawingFigure 2
  • EP3421961B1 patent drawingFigure 3

AI summary

A pressure detection device 20 includes: a piezoelectric element 33 that detects a pressure change via a diaphragm head 32 or the like; a circuit board 57 that is provided with a processing circuit that performs electrical processing with respect to a charge signal outputted from the piezoelectric element 33; a conductive housing member 56, which has conductivity and is disposed to cover (house) the circuit board 57, and which is connected to the ground of the circuit board 57; and a housing (a leading end side housing 31, the diaphragm head 32 and a rear end side housing), which houses the piezoelectric element 33, the circuit board 57 and the housing member 56, and which is electrically insulated from the piezoelectric element 33, the circuit board 57 and the housing member 56.