Ultrasonic Motor Adhesive Layer Thickness Control
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Solution Overview
Problem
Conventional bonding techniques between piezoelectric elements and vibration plates in ultrasonic motors face issues with adhesive layer thickness variations due to warping and surface roughness, leading to separation defects and impaired ultrasonic flaw inspections.
Innovation Solution
The use of an adhesive layer comprising 50-80 parts by mass of organic particles with a number average particle size of 5-15 μm, relative to 100 parts by mass of resin, helps in reducing separation by acting as a spacer and maintaining uniform bonding, thereby improving the bonding interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pressurizing force is increased to reduce the thickness of the adhesive layer, then the adhesive layer thickness is reduced, but separation defects occur in the bonding portion
Solution Approach 1:
The patent changes the particle size parameter of the filler material from conventional fine particles (1-5 μm) to coarse particles (5-15 μm). This parameter change allows the adhesive layer to maintain uniform thickness without requiring excessive pressurizing force, thereby preventing separation defects while achieving the desired thickness control.
Solution Approach 2:
The patent uses a composite adhesive material containing coarse organic particles (5-15 μm) dispersed in the adhesive matrix. This composite structure provides both thickness control through the particle spacer effect and sufficient bonding strength to prevent separation, resolving the contradiction between thin layer requirement and bonding reliability.
2Manufacturing precision
If silica fine particles (1-5 μm) are used in the adhesive to control thickness, then adhesive layer thickness is managed, but cracks occur in the electrode layer due to warping
Solution Approach 1:
The patent changes the particle size parameter from fine (1-5 μm) to coarse (5-15 μm). The larger particle size reduces the number of particles that can penetrate into the electrode layer, thereby preventing cracks while still providing effective thickness control through the particle spacer mechanism.
Solution Approach 2:
The coarse organic particles act as intermediary spacers between the piezoelectric element and the fixed member. They maintain a uniform adhesive layer thickness without requiring high pressurizing force, thus preventing the electrode layer from cracking while still achieving precise thickness control.
3Manufacturing precision
If conventional fine particles are used in the adhesive, then adhesive layer thickness can be controlled, but uniform bonding is difficult to achieve due to warping variations
Solution Approach 1:
The patent changes the particle size parameter to coarse particles (5-15 μm), which provide more stable spacing and better uniformity in the adhesive layer. The larger particles are less sensitive to variations in warping, thereby achieving more consistent bonding uniformity across different piezoelectric elements.
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 approach effectively reduces interfacial separation and maintains excellent impedance characteristics, ensuring reliable ultrasonic motor performance and passing ultrasonic flaw evaluations.
Implementation Method 1
an adhesive layer which is obtained by a resin containing 50 parts by mass or more and 80 parts by mass or less of organic particles having a number average particle size of 5 μm or more and 15 μm or less, relative to 100 parts by mass of the resin
Implementation Method 2
a piezoelectric element including a piezoelectric ceramic having an electrode
Data Source
AI summary
A vibrator includes a piezoelectric element including a piezoelectric ceramic having an electrode, a vibration plate, and an adhesive layer between the piezoelectric element and the vibration plate, wherein the adhesive layer is obtained by a resin containing 50 parts by mass or more and 80 parts by mass or less of organic particles having a number average particle size of 5 μm or more and 15 μm or less, relative to 100 parts by mass of the resin.