Disk Drive Arm Actuator Using Ultrasonic Piezo Motors
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Solution Overview
Problem
Dual actuator hard disk drives (DAHDs) with voice coil motors face issues of high power consumption, heat generation, cost, size, mass, and assembly complexity, limiting performance and reliability.
Innovation Solution
Employing piezoelectric ultrasonic motors (USMs) to independently actuate multiple head stack assemblies, allowing simultaneous operation of read/write heads for increased performance and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If voice coil motors are used to actuate multiple head stack assemblies, then operational speed is improved, but power consumption increases
Solution Approach 1:
The patent replaces voice coil motors (electromagnetic actuation) with piezoelectric ultrasonic motors (piezoelectric actuation). The piezoelectric elements convert electrical energy to mechanical motion through ultrasonic vibrations, eliminating the need for continuous electromagnetic fields and reducing power consumption while maintaining high-speed operation capability.
Solution Approach 2:
The piezoelectric ultrasonic motor operates by applying periodic ultrasonic frequency vibrations to the piezoelectric elements. This periodic action at ultrasonic frequencies (typically 20-100 kHz) creates the necessary mechanical motion for actuating the head stack assemblies, enabling high-speed operation with reduced continuous power consumption compared to voice coil motors.
2Speed
If voice coil motors are used to actuate multiple head stack assemblies, then operational speed is improved, but heat generation increases
Solution Approach 1:
The patent replaces voice coil motors with piezoelectric ultrasonic motors, substituting electromagnetic conversion with piezoelectric conversion. This eliminates the resistive heating inherent in electromagnetic coils and reduces heat generation while maintaining the ability to achieve high operational speeds through ultrasonic vibration-driven mechanical motion.
3Speed
If voice coil motors are used to actuate multiple head stack assemblies, then operational speed is improved, but device complexity increases
Solution Approach 1:
The patent integrates the piezoelectric elements directly into the actuator arm structure, merging the motor function with the actuator mechanism. This consolidation eliminates separate voice coil motor assemblies and their associated mounting structures, reducing overall device complexity while maintaining high-speed actuation capability through the piezoelectric ultrasonic motor system.
4Speed
If voice coil motors are used to actuate multiple head stack assemblies, then operational speed is improved, but mass increases
Solution Approach 1:
The patent replaces the electromagnetic voice coil motor system with a piezoelectric ultrasonic motor system. The piezoelectric elements and their associated structures are significantly lighter than voice coil motors of equivalent performance, reducing the mass of moving components while maintaining high-speed actuation capability through ultrasonic vibration mechanisms.
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
The use of piezoelectric ultrasonic motors enhances DAHD performance by doubling operational speeds, reducing power consumption, heat generation, and simplifying assembly, while maintaining a compact design.
Implementation Method 1
The first piezoelectric motor comprises a first piezoelectric element and a first contact tip. The first piezoelectric element comprises a first mounting surface. The first contact tip is disposed at the first mounting surface, wherein the first contact tip is configured to frictionally contact the first engagement surface to pivot the first head stack assembly about the longitudinal axis.
Implementation Method 2
Employing piezoelectric ultrasonic motors (USMs) to independently actuate multiple head stack assemblies
Implementation Method 3
the first contact tip is configured to frictionally contact the first engagement surface to pivot the first head stack assembly about the longitudinal axis
Data Source
AI summary
A data storage device includes a stack of data storage disks, a head stack assembly, and a piezoelectric motor. The head stack assembly includes an arm, a load beam, a head and a tail. The arm is configured for pivotal motion about a longitudinal axis of an actuator shaft. The load beam is attached to the arm. The head is attached to the load beam and is configured to interact with a surface of one of the disks, the surface defining an x-y plane. The tail is disposed on an opposite side of the actuator shaft from the arm and has a first engagement surface that is parallel to the x-y plane. The piezoelectric motor includes a piezoelectric element and a contact tip. The piezoelectric element comprises a first mounting surface. The contact tip is disposed at the first mounting surface and frictionally contacts the engagement surface.