Disk Drive Head Positioning via Piezoelectric Vertical Actuation

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Solution Overview

Problem

The high cost of hard disk drive (HDD) systems is largely due to the need for multiple read/write heads to access each disk surface, which increases the cost of supporting structures, cabling, and electronics, especially in systems with large numbers of disks.

Innovation Solution

Implementing a system with fewer read/write heads that can move to access multiple disk surfaces using a piezoelectric motor and head suspension arms, allowing a single or dual head to access all disks in a stack, thereby reducing the number of heads and associated components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple read/write heads are used to access each disk surface, then data access speed and reliability are improved, but system cost and device complexity increase significantly

Engineering Contradiction:

Improvedata access reliabilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A single read/write head is designed to perform multiple functions by sequentially accessing different disk surfaces. The head is moved vertically along the spindle axis to access multiple surfaces, making one head universal for multiple storage media rather than requiring dedicated heads for each surface.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The read/write head is made dynamically movable along the vertical axis through a threaded rod mechanism driven by a piezoelectric motor. This dynamic positioning capability allows the head to access different disk surfaces on demand, replacing the static one-head-per-surface configuration.

Inventive Principle:

Principle #15Dynamics

2Productivity

If multiple read/write heads are used for each disk surface, then data access capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvedata access capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates redundant read/write heads from the system. By removing unnecessary heads while maintaining data access capability through the movable head mechanism, the system reduces component count, material costs, assembly complexity, and manufacturing expenses.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

One read/write head is designed to serve multiple disk surfaces sequentially, reducing the total number of heads required. This multi-functionality approach lowers per-head cost allocation while maintaining overall system productivity for data access.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If fewer read/write heads are used, then cost is reduced, but data access speed may be compromised

Engineering Contradiction:

Improvesystem costVSAvoiddata access speed

Core Design Contradiction:

Ease of manufactureVSSpeed

Solution Approach 1:

The piezoelectric motor enables rapid vertical movement of the read/write head along the threaded rod, allowing quick transitions between disk surfaces. This dynamic positioning minimizes access time penalties associated with having fewer heads, maintaining data access speed despite reduced head count.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The piezoelectric motor provides precise and rapid actuation of the read/write head position, replacing slower traditional mechanical actuation mechanisms. This substitution enables fast head repositioning between surfaces, compensating for the reduced number of heads and maintaining high data access speeds.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach significantly reduces the cost of HDD systems while maintaining data access quality, particularly beneficial for systems with large amounts of 'cold' data, by minimizing the number of read/write heads and associated electronics.

Implementation Method 1

a piezoelectric motor moveable along a threaded rod

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

slider 32 carrying a transducing or read/write head (not visible). Each slider 32 is supported by suspension assembly 30... with slider 32'sliding' or 'flying' across disk 22 on a cushion of air, often referred to as an air bearing

Methodology Applied

Scientific EffectAir bearing: Air Lubrication

Data Source

PatentUS20190147909A1Disk drive having multiple disks accessible by a reduced number of read/write heads

Publication Date: 2019.05.16 SEAGATE TECH LLC

AI summary

A disk drive including multiple magnetic recording disks and at least one read/write head, wherein the disk drive includes a rotatable center block having a vertical axis and a mounting member, a first motor attached to the center block for rotating the center block about the vertical axis, a vertical threaded rod positioned in the mounting member, a second motor moveable along the vertical threaded rod, at least one head suspension arm extending outwardly from the second motor, and at least one read/write head mounted to a distal end of one of the arms. The disk drive further includes multiple disks in a stack, wherein at least one of the arms is vertically moveable along the vertical threaded rod by the second motor to position the at least one read/write head in a position to access data on one of the disk surfaces of the plurality of disks.