Sensor Unit Vibration Isolation via Low Modulus Joining Member
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Solution Overview
Problem
Traditional sensor units with inertial sensors are susceptible to noise vibrations, leading to instability and reduced detection accuracy due to the influence of external vibrations, particularly in applications like car navigation systems where engine operations can transmit noise vibrations directly to the sensors.
Innovation Solution
A sensor unit configuration where the inertial sensor module is joined to the outer case via a ring-shaped joining member with a lower elastic modulus, providing a stable and vibration-proof connection that reduces the transmission of noise vibrations and enhances detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the substrate is suspended using springs or elastic members to reduce noise vibration transmission, then the influence of noise vibrations is attenuated, but the substrate position becomes unstable due to floating and tilting under gravity
Solution Approach 1:
A vibration-proof member is introduced as an intermediary component between the outer case and the substrate. This member has lower rigidity than both the outer case and the substrate, allowing it to absorb and attenuate noise vibrations while maintaining stable positional support for the substrate, thus resolving the contradiction between vibration isolation and position stability
Solution Approach 2:
The rigidity parameter of the joining structure is optimized by selecting a vibration-proof member with specific rigidity characteristics - lower than the outer case and substrate but sufficient to maintain positional stability. This parameter adjustment allows the structure to filter vibrations while preventing substrate floating and tilting
2Reliability
If the substrate is directly fixed to the bottom surface to ensure stable position, then position stability is maintained, but noise vibrations are directly transmitted to the sensor
Solution Approach 1:
The vibration-proof member serves as a mediator between the rigid outer case and the substrate. It provides stable mechanical support while its lower rigidity characteristics enable it to decouple vibration transmission paths, thus simultaneously achieving position stability and vibration isolation
3Reliability
If the substrate is suspended with high rigidity to prevent tilting under gravity, then position stability is improved, but noise vibrations are more effectively transmitted to the sensor
Solution Approach 1:
The rigidity of the supporting structure is precisely controlled to be lower than both the outer case and substrate. This parameter change creates an optimal balance where the structure is sufficiently rigid to prevent substrate tilting under gravity but flexible enough to attenuate high-frequency noise vibrations
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 proposed configuration increases the reliability and stability of the sensor unit by minimizing the impact of noise vibrations, resulting in improved detection accuracy and broader environmental adaptability.
Implementation Method 1
The sensor module is joined to the bottom wall of the outer case via a joining member... providing a stable and vibration-proof connection that reduces the transmission of noise vibrations
Data Source
AI summary
A sensor unit with high reliability and stable detection accuracy against vibrations of an installation target object is to be provided.A sensor unit includes: a sensor module configured including a substrate with inertial sensors mounted thereon, and an inner case in which the substrate is installed; and an outer case accommodating the sensor module. A recessed part is formed in the inner case. The inertial sensors are arranged in an area overlapping with the recessed part as viewed in a plan view seen from the direction of thickness of the substrate, and a filling member is provided to fill a space formed by the substrate and the recessed part. The sensor module is joined to a bottom wall of the outer case via a joining member.