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Integrated Separate Magnet For Improved Latch Bias Torque

IP.com Disclosure Number: IPCOM000014418D
Original Publication Date: 2002-Jun-30
Included in the Prior Art Database: 2003-Jun-19

Publishing Venue



Disclosed is a system that allows for an inertial latch system to be integrated into a low stray field VCM (Voice Coil Motor). Generating a large stray field for the inertial latch is very difficult as magnets become more and more thinner (as in 2.5 in laptop drives). A solution is that a separate magnet be dedicated to the inertial latch rather than the use of stray field. However assembly of a totally separate magnet is not only a tolerance issue but also a cost issue. One solution is to integrate a "Bump" or protrusion from the main VCM magnet, which in all practicality is feasible. The drawback of such a design is the imbalance of magnetic forces within the VCM. This imbalance of forces causes out of plane loads on the system, which can lead to performance degradation within the Hard Disk Drive. The above solution incorporates a large transition zone of non-magnetically charged magnet. In a sense, creating a "dead zone" which doesn't cause the imbalance of VCM forces. In addition, the assembly of such a design is much simpler in that the separate magnet bumps is part of the main Magnet body. The transition zone is generated by tooling at the VCM supplier and can be easily tuned for width length. The above system requires but is not exclusive to an inertial style latching system but can be used in latching systems that use magnetic force to lock the Actuator Carriage of the HDD.