HSA Elevator Z-Height Adjustment via Head Feedback
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Solution Overview
Problem
Hard disk drives (HDDs) face challenges in maintaining optimal head-disc spacing (z-height) due to variations in disc thickness, tilt, and environmental changes, leading to issues like head resonance, modulation failures, and reduced recording capacity, as existing technologies struggle to accurately adjust and maintain this spacing.
Innovation Solution
A data storage device with a head stack assembly (HSA) that includes a load beam and a head gimbal assembly, where an elevator mechanism linearly moves the HSA along a shaft to adjust the z-height based on feedback signals from piezoelectric sensors, heaters, and reader-based feedback, ensuring precise positioning and contact with the disc surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the head stack assembly is moved to adjust z-height, then head-disc spacing precision is improved, but device complexity increases due to additional feedback mechanisms and actuators
Solution Approach 1:
The patent implements feedback mechanisms including piezoelectric sensors that detect head-disc spacing and provide signals to the control system, enabling continuous monitoring and adjustment of z-height to maintain optimal spacing despite variations in disc thickness and tilt
Solution Approach 2:
The patent replaces traditional mechanical adjustment mechanisms with piezoelectric actuators that can precisely control head stack assembly position through electrical signals, enabling finer control resolution and reduced mechanical complexity
2Measurement precision
If multiple feedback signals from different sources are used to adjust z-height, then positioning accuracy is improved, but processing complexity and time increase
Solution Approach 1:
The patent performs preliminary calibration of multiple feedback signal sources during manufacturing or initial operation, establishing baseline relationships between different sensors and the actual z-height, which reduces the computational burden during real-time operation
Solution Approach 2:
The patent integrates multiple feedback signals from piezoelectric sensors, capacitive sensors, and reader-based feedback into a unified control algorithm that continuously adjusts z-height based on the combined information, improving positioning accuracy through multi-source validation
3Adaptability or versatility
If the elevator mechanism is used to linearly move the HSA, then z-height adjustability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent designs the elevator mechanism to serve multiple functions: it not only adjusts z-height but also provides a mounting structure for sensors, acts as a support for the head stack assembly, and integrates with the actuator mechanism, thereby reducing the need for separate components
Solution Approach 2:
The patent combines the elevator mechanism with the actuator assembly and sensor mounting structure into a single integrated unit, reducing the number of discrete parts and simplifying manufacturing and assembly 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 solution allows for precise control of z-height, reducing the risk of head resonance and modulation failures, increasing recording capacity by accessing more outer diameter tracks, and maintaining optimal head-disc spacing despite environmental changes.
Implementation Method 1
receiving a first feedback signal from a piezoelectric sensor in the HSA
Data Source
AI summary
A data storage device (DSD) includes a base-deck, a disc above the base-deck, and a shaft extending perpendicular from the base-deck. The DSD also includes a head stack assembly (HSA) including a head gimbal assembly having a load beam and a head at a first end of the HSA. The head interacts with a surface of the disc. The HSA also includes a second end movably mounted on the shaft. The DSD additionally includes an elevator that linearly moves the HSA along the shaft to adjust a distance between the load beam and the surface of the disc in response to receiving a feedback signal associated with the interaction of the head with the surface of the disc. The feedback signal is one of a plurality of feedback signals employed by the elevator to adjust the distance between the load beam and the surface of the disc.