Vibration Device Bonding Structure for Stress Distribution

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Solution Overview

Problem

Existing vibration devices suffer from insufficient bonding strength between the elastic plate and the base member, leading to stress concentration and fatigue failure during vibration.

Innovation Solution

A vibration device design featuring a first elastic plate with multiple bonding portions along its width direction, where the second bonding portion is closer to the end portion than the first, and made of austenitic SUS material, with laser welding to enhance bonding strength and reduce stress concentration, while a mass adding member is attached to increase vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a single bonding portion is used to bond the elastic plate and base member, then the device structure is simple, but the bonding strength is insufficient and stress concentration occurs

Engineering Contradiction:

Improvebonding strengthVSAvoidbonding structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The bonding structure is divided into multiple bonding portions (first bonding portion and second bonding portion) positioned at different locations along the length direction of the elastic plate. This segmentation distributes the bonding load, prevents stress concentration at a single point, and enhances overall bonding strength while maintaining reasonable structural complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different bonding portions are positioned at specific locations (first bonding portion at one end, second bonding portion at the other end) to create non-uniform stress distribution that matches the vibration pattern. This local quality approach ensures that each bonding portion handles the stress appropriately for its position, preventing fatigue failure

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple bonding portions are added to increase bonding strength, then the bonding strength improves, but the manufacturing complexity increases

Engineering Contradiction:

Improveresistance to fatigue failureVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The positions of bonding portions are strategically changed along the length direction of the elastic plate, with the first bonding portion at one end and the second bonding portion at the other end. This parameter change in positioning optimizes stress distribution during vibration while keeping the manufacturing process manageable

Inventive Principle:

Principle #35Parameter changes

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 achieves high bonding strength, reduces the likelihood of cracking, and increases productivity by efficiently propagating heat and stress, making the device more durable and effective in vibration notification functions.

Implementation Method 1

a piezoelectric vibration element 4 on at least one of the first and second surfaces 2a7, 2a8 of the first elastic plate 2a

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

when the first elastic plate is made of an austenitic SUS material or the like, and the first and second bonding portions are formed by irradiation with laser light

Methodology Applied

Scientific EffectLaser heating: Laser

Data Source

PatentUS11453029B2Vibration device and method of manufacturing the same

Publication Date: 2022.09.27 MURATA MFG CO LTD

AI summary

A vibration device that includes a first elastic plate having a first end portion and a second end portion, and a first surface and a second surface facing each other and connecting the first and second end portions. A second elastic plate is laminated to the second end portion of the first elastic plate, and a piezoelectric vibration element is provided on at least one of the first surface and the second surface of the first elastic plate. On a portion where the first elastic plate and the second elastic plate are laminated, a first bonding portion and a second bonding portion that bond the first elastic plate and the second elastic plate to each other are provided. The second bonding portion is located closer to the first end portion than the first bonding portion.