Piezoelectric Actuator Resin Coating for Particle Prevention
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Solution Overview
Problem
Conventional magnetic disc apparatuses face issues with piezoelectric ceramic particles falling off due to the expansion and contraction of piezoelectric actuators, leading to decreased reliability and accuracy in moving the magnetic head, and the manufacturing process is complex with a high production cost.
Innovation Solution
A piezoelectric actuator with a piezoelectric body having recessed portions on its side surfaces, covered by a coating layer made of resin with an uncured-state viscosity between 1 mPa·s and 100 mPa·s, ensuring the coating layer adheres to the surfaces and prevents particle fallout, and a method for manufacturing this actuator that simplifies the process by applying the resin to the cut surfaces and curing it to form a thin, effective coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is provided after the piezoelectric actuator is assembled, then piezoelectric ceramic particles are prevented from falling off, but the resin can stick to unintended places and the manufacturing process becomes complex
Solution Approach 1:
The coating layer is applied to the piezoelectric body before the actuator is assembled into the magnetic disc apparatus. This preliminary coating prevents particles from falling off during subsequent assembly and operation, while avoiding the complexity of post-assembly coating application and preventing resin contamination of other components.
2Manufacturing precision
If a low viscosity resin is used for the coating layer, then the resin can penetrate fine recessed portions, but the coating layer becomes thin and may fall off
Solution Approach 1:
The patent specifies an optimal viscosity range (1-1000 mPa·s) for the uncured resin that balances penetration capability and coating integrity. This parameter optimization allows the resin to sufficiently penetrate fine recessed portions while maintaining adequate film strength and adhesion to prevent coating layer fallout.
3Ease of manufacture
If the uncured-state viscosity of the resin is low (100-1000 mPa·s), then the resin can be applied easily, but it does not get into the bottoms of fine recessed portions and the coating layer falls off
Solution Approach 1:
The patent defines a specific viscosity range (1-1000 mPa·s) for the uncured resin that optimizes both applicability and penetration. This parameter control ensures the resin can be easily applied while sufficiently penetrating fine recessed portions to create a durable coating layer that resists fallout during actuator operation.
4Reliability
If the coating layer is thick, then it effectively covers the surface, but it impairs the displacement of the piezoelectric actuator and deteriorates accuracy
Solution Approach 1:
The patent optimizes the coating layer thickness to be as thin as possible while still providing effective particle protection. By controlling the resin viscosity and applying a minimal sufficient coating, the design achieves particle prevention without significantly impairing the piezoelectric actuator's displacement characteristics or positioning accuracy.
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 solution effectively prevents piezoelectric ceramic particles from falling off, enhancing the reliability and accuracy of magnetic head movement while simplifying the manufacturing process and reducing production costs by ensuring the coating layer remains intact and does not inhibit the actuator's displacement characteristics.
Implementation Method 1
the piezoelectric body expands and contracts upon application of a voltage to the external electrodes
Implementation Method 2
a coating layer made of resin and provided on the four side surfaces. The coating layer covers the recessed portions in the four side surfaces
Data Source
AI summary
A piezoelectric actuator that includes (a) a piezoelectric body made of piezoelectric ceramic, the piezoelectric body having two principal surfaces facing each other and having four side surfaces, (b) external electrodes on the principal surfaces, (c) recessed portions in the four side surfaces, and (d) a coating layer made of resin and provided on the four side surfaces. The coating layer covers the recessed portions in the four side surfaces.