Ultrasonic Sensor Protruding Bottom Case Design
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Solution Overview
Problem
Conventional ultrasonic sensors with piezoelectric elements face challenges in maintaining detection accuracy while preventing damage from external loads, as increasing the thickness of the case to enhance durability can lead to reduced amplitude and detection accuracy.
Innovation Solution
The ultrasonic sensor design incorporates a multilayer piezoelectric element with a protruding portion on the bottom case, which increases thickness only where necessary, reducing the risk of damage and maintaining detection accuracy by optimizing the vibration mode and preventing electrical conduction issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the bottom portion of the case is increased to suppress damage from external loads, then the strength and durability are improved, but the amplitude of vibration is reduced leading to deterioration in detection accuracy
Solution Approach 1:
The invention applies local quality by providing a protruding portion at a specific location on the bottom portion of the case, rather than uniformly increasing the thickness throughout. The protruding portion is positioned at a location away from the cylindrical portion to locally enhance strength where needed while preserving vibration amplitude in the critical sensing area. This localized reinforcement resolves the contradiction by strengthening the bottom portion against external loads without compromising the amplitude required for detection accuracy.
2Strength
If a cover is used to protect the ultrasonic sensor against external loads, then the protection strength is improved, but the detection accuracy deteriorates due to interference with ultrasonic wave transmission
Solution Approach 1:
The invention extracts the protective function from a separate cover component and integrates it directly into the bottom portion of the case through the protruding portion. By incorporating the reinforcement structure within the case itself rather than adding an external cover, the design provides protection against external loads while avoiding the interference that a separate cover would cause to ultrasonic wave transmission. This resolves the contradiction by maintaining protection strength without compromising detection accuracy.
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 design enhances the sensor's resistance to impact without compromising detection accuracy, reducing the occurrence of damage and maintaining effective vibration and electrical insulation.
Implementation Method 1
an ultrasonic sensor including a piezoelectric element (50)... causes the bottom portion of the case to perform bending vibration
Implementation Method 2
transmits and receives ultrasonic waves by causing the bottom portion of the case to perform bending vibration
Data Source
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AI summary
An ultrasonic sensor (100) includes: a case (60) having a cylindrical shape with a bottom, the case (60) including a bottom portion (62) and a cylindrical portion (61) and being formed of a member having conductivity; and a piezoelectric element (50) bonded to an inner surface (62s) of the bottom portion (62). The bottom portion (62) is provided with a protruding portion (62u) protruding toward an opening (60y) side of the case at a position distanced from the cylindrical portion (61). A top surface of the protruding portion (62u) includes a first top surface portion (62a1) and a second top surface portion (62b) having a protrusion height higher than that of the first top surface portion. In a plan view of the piezoelectric element (50) and the second top surface portion (62b) along a direction perpendicular to the second top surface portion (62b), the piezoelectric element (50) is arranged such that at least a part thereof overlaps with the second top surface portion (62b).