Trace Gimbal Structure for High Yaw and Low Roll Stiffness
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Solution Overview
Problem
As track density in hard disk drives increases, it becomes difficult for motor and servo control systems to quickly and accurately position the read/write head over the desired track, necessitating improved head slider positioning control.
Innovation Solution
A trace gimbal design with outer struts, including front and rear outriggers and a middle strut, supports a slider tongue and incorporates microactuators, featuring a slot in the inner strut to maintain high yaw frequency and reduce roll stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If track density is increased to achieve higher storage capacity, then storage capacity increases, but head slider positioning accuracy deteriorates
Solution Approach 1:
The suspension system is divided into two independent actuation stages: a voice coil motor at the base plate for coarse positioning and a piezoelectric microactuator on the flexure for fine positioning. This segmentation allows each actuator to operate optimally within its range, achieving both high tracking speed and high positioning precision required for high-density drives
Solution Approach 2:
The piezoelectric microactuator serves as an intermediary device between the coarse positioning system and the head slider. It receives commands from the servo system and makes precise adjustments to the head slider position, enabling accurate tracking of high-density tracks that the voice coil motor alone cannot achieve
2Measurement precision
If a piezoelectric microactuator is added to the flexure for fine tracking, then tracking precision improves, but device complexity increases
Solution Approach 1:
The patent combines two different actuation technologies (voice coil motor and piezoelectric microactuator) into a single integrated suspension system. The base plate voice coil motor handles large-range positioning while the flexure-mounted piezoelectric actuator handles fine adjustments, merging coarse and fine positioning functions into one cohesive system
Solution Approach 2:
The dual-stage actuation system provides multi-functionality by enabling both high-speed coarse positioning and high-precision fine positioning within a single suspension assembly. This universal design allows the system to handle both the speed and precision requirements of modern high-density disk drives
3Strength
If the inner strut is made stiffer to support the microactuator, then structural strength improves, but roll stiffness increases reducing tracking accuracy
Solution Approach 1:
The slot is positioned specifically in the central portion of the inner strut where it experiences minimal bending moments during normal operation. This local modification maintains structural strength in critical areas while reducing stiffness only where beneficial for roll motion, allowing the microactuator to function effectively without compromising overall structural integrity
Data Source
AI summary
A trace gimbal is described herein. In some embodiments, the trace gimbal includes outer struts including a front outrigger at a distal end of the trace gimbal and a rear outrigger at a proximal end of the trace gimbal. The front outrigger includes a distal front outrigger and a proximal front outrigger, and the rear outrigger includes a distal rear outrigger and a proximal rear outrigger. The trace gimbal further includes a middle strut extending in a width direction of the trace gimbal and adjoining the proximal front outrigger to the rear outrigger, and an inner strut connecting the middle strut to a slider tongue. The inner strut includes a slot, and the inner strut and the middle strut adjoin the outer gimbal struts to the slider tongue.