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Motor Magnet Assembly Process

IP.com Disclosure Number: IPCOM000036765D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Young, JT: AUTHOR

Abstract

A process is described in which magnets made of plastic neodymium iron boron (Ne/Fe/B) are moulded directly into the hub of spindle motors used to drive disk files. The method eliminates post machining of compression-moulded plastic neodymium magnets in precision spindle/ motor assemblies and minimizes critical machining of the magnet housing. It also eliminates a bonding operation and improves magnet contamination control. The process allows a single integral magnet to be formed by successive addition of sections.

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Motor Magnet Assembly Process

A process is described in which magnets made of plastic neodymium iron boron (Ne/Fe/B) are moulded directly into the hub of spindle motors used to drive disk files. The method eliminates post machining of compression-moulded plastic neodymium magnets in precision spindle/ motor assemblies and minimizes critical machining of the magnet housing. It also eliminates a bonding operation and improves magnet contamination control. The process allows a single integral magnet to be formed by successive addition of sections.

In the process a motor housing 1 is rough machined or sintered (Fig. 1). Only features necessary to assemble the magnet are required at this stage, but other features may be added at the manufacturer's discretion.

Green magnets are produced, and the first green magnet 2 is assembled in the housing. The housing acts as part of the moulding tool, and the magnet 2 is formed by compression and heat to its final size, shape and density inside the housing (Fig. 2).

A second green magnet 3 is then assembled in the housing, and the process is repeated (Fig. 3). This process can apply regardless of the number of compression mouldings, and is limited only by the tooling strength.

Other items could be trapped between the magnets, if required, and the process could apply to non-magnetic compression mouldings. Thermal expansion coefficients of plastic neodymium magnets and steel mean that this process is particularly useful for these m...