Electronic Device Case Cover Vibration Control via Mass Segmentation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing solutions for reducing vibration in electronic device cases, such as those used in electric vehicle diving units, face challenges in balancing rigidity enhancement with weight minimization and natural frequency adjustment to avoid resonance and human hearing sensitivity issues.

Innovation Solution

A case structure with a cover that includes an annular first region, a second region with increased mass per unit area, a third region with lower rigidity, and a reinforcement portion with a notch, allowing for adjustable natural frequency and effective vibration suppression without excessive weight increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rigidity of the upper case is increased by providing a rib from the center portion toward the fastening portion, then the vibration of the upper case is reduced, but the weight of the upper case becomes excessively large

Engineering Contradiction:

Improverigidity of the upper caseVSAvoidweight of the upper case

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The upper case is divided into multiple regions (first region with fastening portions, second region with higher mass per unit area, third region with lower mass per unit area). This segmentation allows different regions to have different mass distributions, enabling vibration suppression through mass concentration in the second region without requiring excessive ribs throughout the entire structure, thus controlling overall weight.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mass per unit area is made non-uniform across different regions of the upper case. The second region has a larger mass per unit area compared to the third region, creating local mass concentration at specific locations. This local quality variation allows targeted vibration suppression without uniformly increasing the weight of the entire upper case.

Inventive Principle:

Principle #3Local quality

2Strength

If the rigidity of the upper case is increased by the rib, then the primary natural frequency increases to 1 kHz to 5 kHz, but this frequency range has high human hearing sensitivity

Engineering Contradiction:

Improverigidity of the upper caseVSAvoidhuman hearing sensitivity to vibration frequency

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The mass distribution parameters of the upper case are changed by creating regions with different mass per unit area. The second region has a larger mass per unit area, which modifies the vibrational characteristics and natural frequency of the upper case. This parameter change allows the natural frequency to be adjusted to a range below 1 kHz or above 5 kHz, avoiding the high human hearing sensitivity range of 1-5 kHz.

Inventive Principle:

Principle #35Parameter changes

3Strength

If the rigidity of the upper case is increased by the rib, then the vibration is reduced, but the upper case may resonate with the lower case due to increase in rigidity

Engineering Contradiction:

Improverigidity of the upper caseVSAvoidresonance avoidance between upper and lower case

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The upper case has non-uniform mass distribution with the second region having larger mass per unit area. This local mass concentration modifies the vibrational modes and natural frequencies of the upper case, making it less likely to resonate with the lower case. The localized mass variation allows rigidity enhancement while maintaining frequency separation from the lower case.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The mass distribution parameters are modified to create regions with different mass per unit area. This parameter change alters the dynamic characteristics of the upper case, including its natural frequencies and mode shapes, thereby reducing the likelihood of resonance with the lower case while maintaining the necessary rigidity for vibration suppression.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12213268B2Case and electronic device equipped with the same

Publication Date: 2025.01.28 ASTEMO LTD

AI summary

Provided are a case having a structure with a high degree of freedom in the adjustment of natural vibration and capable of suppressing vibration without excessively increasing the weight, and an electronic device equipped with the same. A case 3 includes a case body 10 having an accommodating space 10b capable of accommodating a circuit substrate 2 and being opened to one side, and a cover 20 attached to the case body 10 so as to close the opening of the case body 10. The cover 20 includes an annular first region portion 21 in contact with the case body 10, a second region portion 22 located on an inner peripheral side of the first region portion 21, a third region portion 23 located between the first region portion 21 and the second region portion 22 and connected to the first region portion 21 and the second region portion 22, and a rib 25 extending on the third region portion 23 and connected to the second region portion 22. The second region portion 22 is configured such that the mass per unit area when viewed from the attachment direction D of the cover 20 to the case body 10 is larger than the third region portion 23. The rib 25 has a notch 26 provided at a position excluding a distal end portion in the extending direction thereof.