Vibration Actuator Adhesive Layer Thickness Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vibration wave motors face challenges in achieving high-power densification while maintaining adhesion reliability due to stress issues between the piezoelectric element and the elastic body, leading to potential peeling of adhesives.
Innovation Solution
A vibration-type actuator design featuring a vibration body with an electro-mechanical energy conversion element and an elastic body bonded via an adhesive, including a first adhesive layer between the energy conversion element and a flat plate portion, a second adhesive layer with increasing thickness towards a protrusion, and a third adhesive layer near the edge portion, optimizing adhesive thickness and distribution to manage stress and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power densification is pursued in vibration wave motors, then output power increases, but adhesive peeling occurs due to higher stress
Solution Approach 1:
The adhesive layer is designed with spatially varying thickness: thinner near the electro-mechanical energy conversion element and thicker toward the protrusion. This local quality variation allows the adhesive to better accommodate stress distribution, preventing peeling while maintaining high output power capability
Solution Approach 2:
The invention changes the parameter of adhesive layer thickness from uniform to non-uniform, specifically making it increase toward the protrusion. This parameter change optimizes stress distribution in the adhesive layer, enabling the system to achieve high-power densification without adhesive failure
2Strength
If adhesive thickness is increased to improve adhesion, then bonding strength increases, but stress concentration occurs at the protrusion root
Solution Approach 1:
The adhesive layer thickness is optimized locally: thinner regions are positioned where stress concentration would occur (near the energy conversion element and protrusion root), while thicker regions are positioned where additional bonding strength is needed (toward the protrusion tip). This local optimization resolves the contradiction between strength and stress concentration
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 output power and reliable adhesion, reducing stress concentrations and maintaining adhesive strength, thus enabling efficient vibration modes and robust operation.
Implementation Method 1
a piezoelectric element fixed to the reverse side of the elastic body
Implementation Method 2
an adhesive that is generally used to bond a piezoelectric element and an elastic body
Implementation Method 3
The contact body that is in pressure contact with the protrusions then receives frictional drive force (thrust force) from the two projections
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vibration-type actuator includes a vibration body, including an electro-mechanical energy conversion element (4) and an elastic body (3) which are bonded to each other via an adhesive (13), and a contact body in contact with the elastic body. The elastic body includes a flat plate portion (3b) and a protrusion (3a). The vibration-type actuator further includes as part of the adhesive between the electro-mechanical energy conversion element and the flat plate portion, a first adhesive layer (13a), and a second adhesive layer (13b) that is adjacent to the first adhesive layer, a thickness of the second adhesive layer being larger than a thickness of the first adhesive layer and increasing toward the protrusion, or a third adhesive layer (13c) that is adjacent to the first adhesive layer and that is between the first adhesive layer and an edge portion of the electro-mechanical energy conversion element, a thickness of the third adhesive layer increasing toward the edge portion and being 10 µm or less, and a length of the third adhesive layer falling between 100 µm and 400 µm.