Sensor assembly and liquid level detection device

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Solution Overview

Problem

Existing liquid level detection systems in washing machines face challenges with inconvenient maintenance and replacement of pressure sensors, as well as instability during installation due to the complexity of disassembly and reassembly processes.

Innovation Solution

A sensor assembly with a housing featuring a mechanical interface that includes a plug portion with limiting portions for secure engagement with a mounting mechanism, and an electrical interface for easy connection and disconnection, along with a piezoelectric sensor and semiconductor strain gauge for accurate pressure sensing, is designed for stable mounting and easy installation/detachment on a support frame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pressure sensor is mounted in the washing machine, then liquid level detection function is achieved, but maintenance and replacement of the pressure sensor becomes inconvenient

Engineering Contradiction:
Improveliquid level detection functionVSAvoidmaintenance and replacement convenience
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The pressure sensor is separated from the main washing machine body and integrated into a detachable air chamber assembly. This segmentation allows the pressure sensor to remain functional within the sealed air chamber while enabling easy removal of the entire air chamber assembly for sensor maintenance, resolving the contradiction between maintaining detection reliability and improving repair convenience.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a pressure sensor is installed in the washing machine, then liquid level detection is enabled, but the installation process becomes complex and the installed sensor is prone to shaking

Engineering Contradiction:
Improveliquid level detectionVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressure sensor, air chamber, and mounting structure are merged into a single integrated air chamber assembly. This combination simplifies installation by treating the sensor and its mounting structure as one unit, reducing installation complexity while preventing shaking through the integrated rigid structure. The T-shaped housing with built-in mounting ears provides stable attachment to the washing machine drum.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a pressure sensor is mounted directly in the washing machine, then liquid level detection works, but the mounted sensor is easy to shake

Engineering Contradiction:
Improveliquid level detectionVSAvoidsensor mounting stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The mounting ears and mounting holes are pre-integrated into the air chamber housing structure during manufacturing. This preliminary preparation of mounting features ensures stable attachment when the air chamber assembly is installed in the washing machine, preventing sensor shaking while maintaining detection reliability. The rigid T-shaped housing structure with positioned mounting ears provides inherent stability.

Inventive Principle:
Principle #10Preliminary action

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 enables stable and secure mounting of the sensor assembly, facilitating easy installation and maintenance by preventing accidental disengagement and ensuring reliable liquid level detection with improved precision and reduced operational complexity.

Implementation Method 1

a piezoelectric sensor provided in the housing and constructed to sense a pressure inputted from the pressure interface

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a semiconductor strain gauge provided on the printed circuit board, of which a resistance value is varied with the pressure inputted from the pressure interface

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP3290877B1Sensor assembly and liquid level detection device
Publication Date: 2021.04.14 TYCO ELECTRONICS (SHANGHAI) CO LTD
  • EP3290877B1 patent drawingFigure 1
  • EP3290877B1 patent drawingFigure 2
  • EP3290877B1 patent drawingFigure 3

AI summary

A sensor assembly and a liquid level detection device are disclosed. The sensor assembly includes: a housing; a pressure interface provided on the housing and communicated with a pressure transmission tube; a piezoelectric sensor provided in the housing and constructed to sense a pressure inputted from the pressure interface; a mechanical interface provided at one side of the housing and constructed to be detachably engaged with a mounting mechanism; and an electrical interface provided at the other side of the housing and constructed to be electrically connected to a mating electrical interface in a plug manner. A detachable engagement of a mating interface of the mounting mechanism with the mechanical interface of the sensor assembly facilitates installing and detaching the sensor assembly, and enables the sensor assembly to be reliably mounted on support frame.