Gimbal Assembly Linear Actuators for Tracking Precision
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Solution Overview
Problem
In magnetic hard disk drives, the placement of microactuators within the head gimbal assembly poses challenges in design, performance, and manufacturability due to the transmission of reaction forces that can excite undesirable resonances and degrade tracking performance, especially when collocated with read/write heads.
Innovation Solution
A gimbal assembly with linear actuators, such as piezoelectric elements, is designed to induce rotation of the slider by being mounted close to the head area, with a metallic layer and flex circuit configuration that minimizes reaction forces and accommodates heat-assisted magnetic recording (HAMR) devices by optimizing the position and attachment of piezoelectric elements to ensure pure rotary motion and reduce the risk of contact with the recording medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microactuators are collocated with read/write heads in the head gimbal assembly, then tracking precision is improved, but reaction forces excite undesirable resonances that degrade performance
Solution Approach 1:
The patent introduces a specialized mounting structure with flexible arms and damping elements as an intermediary between the microactuator and the head gimbal assembly. This mediator isolates the reaction forces from the main structure, allowing the microactuator to be collocated with the read/write head for improved tracking precision while preventing resonance excitation through the flexible mounting mechanism.
Solution Approach 2:
The patent converts the harmful reaction forces into a beneficial effect by using compliance elements and flexible arms that allow controlled motion. The flexibility in the mounting structure absorbs and dissipates the reaction forces through elastic deformation, transforming what would be harmful resonances into manageable mechanical compliance that actually improves actuator performance.
2Manufacturing precision
If linear actuators are mounted close to the head area, then rotational control is improved, but the risk of contact with the recording medium increases
Solution Approach 1:
The patent positions the linear actuators and their mounting structure in a different spatial dimension relative to the recording medium. By mounting the actuators on the opposite side of the head gimbal assembly from the recording medium, and using extension arms that reach across the structure, the patent achieves close proximity for rotational control while maintaining safe separation from the recording medium through three-dimensional spatial arrangement.
Solution Approach 2:
The patent segments the head gimbal assembly into distinct functional zones: the actuator mounting portion, the flex circuit routing area, and the head/slider assembly. This segmentation allows the linear actuators to be mounted close to the head area for improved rotational control while the physical separation and routing of components prevent contact with the recording medium, improving reliability.
3Ease of manufacture
If flex circuit is routed through the head area, then electrical connection is achieved, but the complexity of assembly increases
Solution Approach 1:
The patent designs the flex circuit to serve multiple functions simultaneously: it provides electrical connections from the linear actuators to the read/write head, acts as a structural support element, and defines the spatial routing path for other components. This multi-functionality reduces assembly complexity by combining several functions into a single integrated component rather than requiring separate elements for each function.
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 solution effectively minimizes reaction forces, enhances tracking performance, and improves operational shock tolerance by ensuring pure rotary motion and proper positioning of linear actuators, reducing the risk of head failure and data loss.
Implementation Method 1
A gimbal assembly with linear actuators, such as piezoelectric elements, is designed to induce rotation of the slider
Data Source
AI summary
A gimbal assembly includes a flex circuit with a first end extending along a loadbeam and second end having bond pads configured to be electrically coupled to a slider. The gimbal assembly includes a metallic layer with a fixed portion fixably attached to the loadbeam and a movable portion fixably attachable to the slider. The movable portion has at least one extension arm coupled to and providing support to the second end of the flex circuit. First and second linear actuators are coupled between the fixed portion and the movable portion. The first and second linear actuators cause a rotation of the slider in response to an electric signal.