Head Gimbal Assembly Balancing Weight Reduces Roll Torque
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Solution Overview
Problem
Conventional head gimbal assemblies in hard disk drives experience increased roll torque during seek operations, leading to potential slider contact with the disk and drive failure, due to high acceleration and deceleration, which is exacerbated by the roll inertia moment, and existing solutions either reduce drive performance or limit storage capacity.
Innovation Solution
The implementation of a head gimbal assembly with a thinner slider, a flexure window to reduce the roll moment arm, and a balancing weight to align the center of mass with the dimple contact point, thereby decreasing the roll torque exerted on the slider during seek operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high acceleration and deceleration are used during seek operations, then data transfer rate and seeking performance are improved, but roll torque increases causing slider contact with the disk
Solution Approach 1:
A balancing weight is added to the head gimbal assembly to counterbalance the roll inertia moment. The balancing weight creates a counteracting torque that offsets the harmful roll torque generated during acceleration and deceleration, allowing high seek performance without slider contact
Solution Approach 2:
The roll inertia moment is reduced by modifying the mass distribution in the head gimbal assembly through the addition of the balancing weight. This changes the inertial parameters of the system to minimize roll torque while maintaining operational performance
2Reliability
If acceleration or deceleration is reduced to decrease roll torque, then slider contact is prevented, but drive performance deteriorates
Solution Approach 1:
The balancing weight provides a counteracting torque that allows the system to maintain high acceleration and deceleration rates without experiencing net roll torque that would cause slider contact, thus preserving drive performance while preventing damage
3Force
If roll inertia moment is reduced by thinning the slider, then roll torque is decreased, but slider structural integrity may be compromised
Solution Approach 1:
Rather than thinning the slider to reduce roll inertia, a balancing weight is added to the head gimbal assembly to counterbalance the roll torque. This approach reduces roll torque without compromising slider thickness or structural integrity
Solution Approach 2:
Instead of modifying the slider thickness (one dimension), the solution adds a balancing weight to the head gimbal assembly, addressing the roll torque problem through a different dimensional approach that doesn't affect slider strength
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 significantly reduces roll torque, enhancing seek performance and preventing slider contact with the disk, while maintaining or improving drive performance and storage capacity.
Implementation Method 1
Changes in the roll torque may equal the acceleration or deceleration multiplied by the roll inertia moment. It is even more preferable to reduce the roll inertia moment.
Implementation Method 2
The implementation of a head gimbal assembly with a thinner slider, a flexure window to reduce the roll moment arm, and a balancing weight to align the center of mass with the dimple contact point, thereby decreasing the roll torque exerted on the slider during seek operations.
Implementation Method 3
The slider flies on the rotating disk with about a 10 nm gap, also known as the flying height, between the slider and the disk.
Data Source
AI summary
In a balanced head gimbal assembly for improved seeking performance, a slider having a magnetic head with a set of read elements to read data and a set of write elements to write data, an air-bearing surface, and a non-air-bearing surface is coupled to a suspension. The suspension includes a loadbeam, a flexure, and a balancing weight. The loadbeam is coupled to an actuator arm. The flexure, coupled to the loadbeam, has a window through which a dimple, coupled to the loadbeam, contacts a dimple contact point. The balancing weight, coupled to the flexure, has a configuration which permits alignment of a center of mass of the head gimbal assembly with the dimple contact point.