Dual Pole Magnet Linear Actuator Resonance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional voice coil actuators in tape data storage machines suffer from out-of-plane resonant vibrations due to asymmetrical mass distribution and flex circuit connections, leading to instability and performance degradation.
Innovation Solution
A dual pole magnet assembly actuated by a stationary dual wound coil, where one part is wound clockwise and the other counter-clockwise, providing additive excitation forces and reducing the likelihood of out-of-plane resonances, eliminating the need for flex circuits and thus preventing fatigue failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional voice coil actuator uses a coil with significant mass distributed about the actuation axis, then the coil can be actuated to move the head assembly, but out-of-plane resonant vibrations occur causing instability and performance degradation
Solution Approach 1:
The coil is divided into two separate coils (first coil and second coil) wound in opposite directions around opposite poles of the magnet assembly. This segmentation allows each coil to be optimized independently and reduces the overall mass distribution away from the actuation axis, thereby reducing out-of-plane resonances while maintaining actuation force.
2Ease of operation
If a flex circuit is used to energize the moving coil, then electrical connection is achieved, but the asymmetrical mass distribution and fatigue failure from repeated cycling occur
Solution Approach 1:
Instead of making the coil movable and connecting it via flex circuit, the invention inverts the approach by making the coil stationary and moving the magnet assembly. The stationary coils are fixed to the housing, eliminating the need for flex circuits and their associated fatigue failure problems, while the magnet assembly moves along the actuation axis.
3Ease of manufacture
If the coil mass is broadly distributed about the actuation axis, then the coil can be wound effectively, but the mass distribution causes out-of-plane resonant vibrations
Solution Approach 1:
The invention uses symmetrical placement of two coils wound in opposite directions around opposite poles. This creates a balanced mass distribution where the asymmetrical winding directions cancel each other's rotational effects, eliminating out-of-plane resonances while maintaining ease of coil winding manufacturing.
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 dual pole magnet assembly with a narrower mass distribution aligned to the actuation axis reduces detrimental resonances, enhancing stability and performance by eliminating flex circuit-related issues.
Implementation Method 1
A stationary dual wound coil provides excitation forces that are applied to both poles of the dual pole magnet. The excitation forces on both of the poles of the actuated dual pole magnet are additive.
Data Source
AI summary
A dual pole linear actuator includes a dual pole magnet assembly that is moved by providing a bi-directional analog DC control signal to a dual wound coil. The dual pole magnet assembly includes a permanent magnet that is flanked by top and bottom pole pieces. The dual wound coil is assembled to an actuator housing with a top part of the coil being wound in one rotary direction, while the bottom part of the coil is wound in the opposite rotary direction.