Piezoelectric Suspension Assembly Adhesion Stability
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Solution Overview
Problem
The existing suspension assemblies for disk devices face challenges in stably adhering and transmitting the driving force from piezoelectric elements due to high precision adhesion requirements, leading to decreased stroke and increased dispersion in the magnetic head's movement.
Innovation Solution
A suspension assembly design featuring a thin metallic plate with a base insulating layer, a conductive layer forming traces, and a cover insulating layer, where the piezoelectric elements are adhered to the cover insulating layer, allowing for stable adhesion and increased stroke without altering the size or characteristics of the piezoelectric elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PZT elements are fixed by their entire surface to a base insulating layer, then adhesion stability is improved, but manufacturing precision requirements increase significantly
Solution Approach 1:
A resin layer is introduced as an intermediary between the PZT element and the base insulating layer. The resin layer has a higher modulus than the base insulating layer and serves as a compliant adhesive medium that accommodates dimensional mismatches between components, reducing the precision requirements for adhesive application while maintaining reliable bonding.
Solution Approach 2:
The mechanical properties of the adhesive system are changed by selecting a resin material with specifically higher modulus compared to the base insulating layer. This parameter change allows the adhesive layer to better transmit piezoelectric forces while accommodating manufacturing tolerances, thus improving reliability without proportionally increasing manufacturing precision requirements.
2Productivity
If preliminary curing of adhesive is not carried out properly, then assembly speed is improved, but PZT element positioning stability deteriorates
Solution Approach 1:
The resin layer is pre-formed as part of the base insulating layer structure before PZT element mounting. This preliminary preparation of the adhesive layer ensures proper positioning and initial stability of PZT elements during assembly, allowing for faster production cycles without sacrificing positioning precision.
3Device complexity
If adhesive amount is not precisely controlled, then manufacturing complexity is reduced, but PZT element adhesion reliability deteriorates
Solution Approach 1:
The resin layer acts as a forgiving intermediary that compensates for variations in adhesive application amount. Its higher modulus and compliant nature allow it to accommodate excess or deficient adhesive without compromising the bonding reliability, thus reducing the complexity of adhesive control processes.
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 design achieves stable adhesion and fixing of actuation elements, enhancing the stroke per unit voltage without changing the piezoelectric elements' characteristics or size, thereby improving the accuracy and precision of the magnetic head's movement.
Implementation Method 1
thin piezoelectric elements (PZT elements) serving as actuation elements are mounted in the vicinity of a gimbal portion of a trace member, and a magnetic head is minutely displaced in a seek direction by expansion and contraction of the piezoelectric elements
Data Source
AI summary
According to one embodiment, a suspension assembly includes a support plate including a distal end portion, a trace member attached to the support plate, an elastic supporting member made from a distal end portion of the trace member and configured to support a head, and an actuation element expandable/contractible in the longitudinal direction of the trace member, at least a part of a bottom of which is adhered to a seating surface formed from a cover insulating layer of the trace member.