Voice Coil Actuator Latch Eddy Current Unlatching
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Solution Overview
Problem
The design of a voice coil actuator latch mechanism for thin hard disk drives (HDDs) faces challenges due to spatial constraints, as existing magnetic attraction-based latches can inhibit latch lever rotation and require additional space, leading to friction and increased height or reduced disk count.
Innovation Solution
A voice coil actuator latch mechanism utilizing an eddy current magnet positioned proximal to the outer perimeter side face of the recording disk, which generates an eddy current force to rotate a latch lever to an unlatched position, allowing the head stack assembly to be securely positioned without increasing the disk drive's height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic attraction-based latch mechanism is used, then the latch lever can be held in position, but the mechanism inhibits latch lever rotation and requires additional space
Solution Approach 1:
The patent replaces the traditional mechanical spring-based latch mechanism with an electromagnetic actuator system. The actuator uses magnetic fields generated by voice coil magnets to engage and disengage the latch lever, eliminating the need for mechanical springs and reducing the overall space required for the latch mechanism while maintaining reliable holding capability.
Solution Approach 2:
The patent changes the operational parameters of the latch mechanism by using electromagnetic force instead of mechanical force. The voice coil magnets generate controlled magnetic fields that can be activated and deactivated electrically, allowing the latch to be engaged and disengaged without the physical space requirements of traditional mechanical spring systems.
2Reliability
If traditional latch mechanism is used, then the head stack assembly can be secured on the ramp, but the mechanism increases the disk drive's height
Solution Approach 1:
The patent repositions the latch mechanism components to utilize the radial space near the disk perimeter rather than occupying vertical space. The voice coil magnets are positioned adjacent to the disk edge, and the latch lever operates in a plane that allows engagement without increasing the drive's height, effectively moving the mechanism from a vertical arrangement to a radial/tangential arrangement.
Solution Approach 2:
The latch mechanism components are nested within the existing drive structure. The voice coil magnets are positioned in the space between the actuator arm and the disk perimeter, and the latch lever is integrated into the base structure, allowing the mechanism to fit within the existing envelope without increasing the overall height of the drive.
3Reliability
If magnetic attraction force is applied to hold latch lever, then latching is achieved, but friction increases and rotation is inhibited
Solution Approach 1:
The patent uses dynamically controllable electromagnetic fields instead of static mechanical springs. The voice coil magnets can be electrically activated to provide holding force only when needed, and deactivated to allow frictionless movement during latching operations. This dynamic control eliminates continuous mechanical contact and friction that would inhibit lever rotation in traditional systems.
Solution Approach 2:
The patent replaces continuous mechanical spring pressure with intermittent electromagnetic holding force. The electromagnetic actuator provides holding force only when electrically activated, eliminating the constant mechanical contact and friction of spring-based systems, thereby enabling smooth lever rotation during engagement and disengagement operations.
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 enables secure latching and unlatching of the head stack assembly while maintaining a low profile, addressing the spatial constraints and operational reliability of thin HDDs by using an eddy current force to rotate the latch lever, thus allowing the head to be loaded onto the disk without increasing the drive's height.
Implementation Method 1
an eddy current magnet configured for positioning proximal to the outer perimeter side face of one or more recording disk, and which cooperates with the conductive side face to generate an eddy current force to rotate a latch lever to an unlatched position
Implementation Method 2
the magnetic attraction between the eddy current magnet and the voice coil actuator yoke generates a latch bias force which causes the end cam and cam follower to engage or mesh in order to hold the latch lever in a latched position
Data Source
AI summary
A voice coil actuator utilizes an eddy current magnet configured for positioning proximal to the outer perimeter side face of one or more recording disk, and which cooperates with the conductive side face to generate an eddy current force to rotate a latch lever to an unlatched position. Embodiments may include an end cam on a base on which the latch lever is rotatably disposed, and the latch lever includes a cam follower capable of rotatably engaging with the end cam, whereby the magnetic attraction between the eddy current magnet and the voice coil actuator yoke generates a latch bias force which causes the end cam and cam follower to engage or mesh in order to hold the latch lever in a latched position.