Ultrasonic Sensor Case Orientation With a Recessed Chamfer

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Solution Overview

Problem

Existing ultrasonic sensors face challenges in identifying the direction of the case due to symmetrical shapes, which complicates the attachment of the piezoelectric element and leads to increased spurious frequency vibrations, affecting detection performance in short distances.

Innovation Solution

The ultrasonic sensor design incorporates a cylindrical case with thick and thin wall portions, featuring a chamfered portion with a recessed mark to identify the case direction without increasing spurious frequency vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a recessed portion is provided on an opening portion side of the case to make the shape asymmetrical, then the direction of the case can be identified, but the intensity of vibration at a spurious frequency increases

Engineering Contradiction:

Improvecase direction identificationVSAvoidspurious frequency vibration intensity

Core Design Contradiction:

Loss of informationVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetry by providing a recessed portion on only one of the thin wall portions (specifically on one of the opposing thin wall portions), creating an asymmetric shape that enables direction identification. This asymmetric feature allows the case to be distinguished in terms of orientation without requiring complete asymmetry of the entire case structure.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The recessed portion is localized to specific regions (thin wall portions) rather than being distributed throughout the case. By concentrating the asymmetric feature in localized areas with thinner wall sections, the patent achieves direction identification while minimizing the overall impact on vibration characteristics compared to making the entire case asymmetric.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the shape of the case is symmetrical, then manufacturing is simplified, but it is difficult to identify the direction of the case and know changes in forming precision

Engineering Contradiction:

Improvecase manufacturing simplicityVSAvoidcase direction identification

Core Design Contradiction:

Ease of manufactureVSLoss of information

Solution Approach 1:

The patent introduces minimal asymmetry through the recessed portion while maintaining overall case symmetry. This approach preserves the simplicity of manufacturing processes for the majority of the case structure while providing just enough asymmetric feature (the recessed portion on thin wall portions) to enable direction identification and forming precision monitoring.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The asymmetric recessed portion is applied locally to thin wall portions rather than to the entire case structure. This localized approach maintains the overall symmetrical shape that simplifies manufacturing while introducing directional identification capability only where needed, thus balancing manufacturing ease with directional information.

Inventive Principle:

Principle #3Local quality

3Loss of information

If the intensity of vibration at a spurious frequency increases, then the case can be identified, but reverberation time increases and detection performance in short distance decreases

Engineering Contradiction:

Improvecase direction identificationVSAvoiddetection performance in short distance

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent uses minimal asymmetry (recessed portion on thin wall portions) to achieve direction identification while avoiding excessive asymmetry that would significantly increase spurious frequency vibrations. The carefully controlled asymmetric feature provides just enough directional information without causing excessive reverberation that would degrade short-distance detection performance.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

By localizing the recessed portion to thin wall portions rather than applying it across the entire case structure, the patent minimizes the overall impact on vibration characteristics. This localized asymmetric feature provides direction identification while limiting the increase in spurious frequency vibration intensity and associated reverberation time that would harm short-distance detection reliability.

Inventive Principle:

Principle #3Local quality

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 design allows for accurate case orientation and reduced spurious frequency vibrations, enhancing detection performance in short distances by providing a visual marker for case orientation.

Implementation Method 1

a piezoelectric element disposed on an inner bottom surface of the case

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an ultrasonic sensor including a cylindrical case with a bottom including a bottom plate and a side wall

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentUS12436026B2Ultrasonic sensor

Publication Date: 2025.10.07 MURATA MFG CO LTD

AI summary

An ultrasonic sensor includes a case including a cylindrical side wall and a bottom plate in one end portion of the side wall, and a piezoelectric element on the bottom plate inside the case. The side wall includes a pair of thick wall portions facing each other and a pair of thin wall portions thinner than the thick wall portions facing each other. An inner peripheral edge of another end portion of the side wall includes a chamfered portion. The chamfered portion of one of the pair of thin wall portions includes a recessed portion.