Piezoelectric Microactuator In-Plane Mounting for Flexure Tongue
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Solution Overview
Problem
Current microactuator designs in disk drives face challenges in providing both adequate stroke and bandwidth for fine actuation, with existing designs often causing excessive vertical deflection of the flexure tongue, which can affect the positioning of read heads and lead to undesirable pitch and roll moments, compromising data track spacing and read head operation.
Innovation Solution
The integration of piezoelectric elements within a compliant actuator frame, closer to the read head, which includes curved compliant members and a dimple contact mechanism to minimize vertical deflection and enhance rotational motion, allowing for precise positioning of the read head while maintaining adequate stroke and bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If piezoelectric microactuators are affixed to the mounting plate or load beam, then adequate stroke is provided, but vertical deflection of the flexure tongue increases excessively
Solution Approach 1:
The patent transitions the microactuator from out-of-plane mounting (on mounting plate or load beam) to in-plane mounting (on the tongue itself). This dimensional change allows the actuator to apply force within the plane of the tongue, generating rotational motion without causing excessive vertical deflection. The in-plane configuration enables the actuator to pivot about an axis within the tongue plane, achieving fine actuation while maintaining tongue stability.
Solution Approach 2:
The patent creates a simplified version of the microactuator system by integrating the piezoelectric element directly into the tongue structure rather than mounting it on separate components. This integration copies the essential actuation function while eliminating the problematic mounting structure that caused vertical deflection. The actuator becomes part of the tongue assembly itself, with the piezoelectric element bonded directly to the tongue surface.
2Speed
If microactuator is disposed closer to the read head, then bandwidth is improved, but stroke is reduced
Solution Approach 1:
The patent changes the mounting parameters of the microactuator by positioning it at a specific location on the tongue (between 0.5mm to 2.0mm from the read head) and orienting it at a specific angle (10 to 45 degrees relative to the tongue longitudinal axis). These parameter optimizations allow the actuator to achieve both high bandwidth and adequate stroke. The angled orientation and precise positioning create a mechanical advantage that amplifies the effective stroke while maintaining the bandwidth benefits of close proximity to the read head.
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 configuration enables improved servo control bandwidth and reduced vertical deflection, ensuring accurate positioning of read heads relative to data tracks on spinning disks, enhancing data access performance and maintaining desired track spacing.
Implementation Method 1
The integration of piezoelectric elements within a compliant actuator frame
Data Source
AI summary
A head gimbal assembly (HGA) for a disk drive includes a mounting plate configured to be attachable to an actuator arm, a load beam extending from the mounting plate, a laminated flexure, first and second piezoelectric elements, and a read head. The laminated flexure includes a fixed portion that is attached to the load beam, and a head mounting tongue that is connected to the fixed portion by first and second compliant members. The read head is bonded to the head mounting tongue. The laminated flexure also includes first and second piezoelectric element receiving windows, each adjacent a respective one of the first and second compliant members. The first and second piezoelectric elements are each disposed within a respective one of the first and second piezoelectric element receiving windows.