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Method And Means for Mechanically Attaching a Ceramic Magnet To the Rotor Shaft

IP.com Disclosure Number: IPCOM000099415D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 2 page(s) / 89K

Publishing Venue

IBM

Related People

Schaefer, JO: AUTHOR

Abstract

Disclosed are method and means for attaching large ceramic magnets (typically larger than 45 mm in diameter) to the shaft. These large magnets have very high peak application torque loadings and require correspondingly high clamping forces to insure no slippage of the magnet with respect to the shaft. The technique employed on the smaller 35 mm rotor, where the force is internal and reacts against the magnet's inside wall surface, results in magnet breakage. However, larger rotors provide more space for outside-of-magnet coupling, and it is thus possible to use constraining means designed to react against the ends of the magnet in a solely compressive mode. This technique completely eliminates the potential for magnet breakage.

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Method And Means for Mechanically Attaching a Ceramic Magnet To the Rotor Shaft

       Disclosed are method and means for attaching large ceramic
magnets (typically larger than 45 mm in diameter) to the shaft.
These large magnets have very high peak application torque loadings
and require correspondingly high clamping forces to insure no
slippage of the magnet with respect to the shaft.  The technique
employed on the smaller 35 mm rotor, where the force is internal and
reacts against the magnet's inside wall surface, results in magnet
breakage. However, larger rotors provide more space for
outside-of-magnet coupling, and it is thus possible to use
constraining means designed to react against the ends of the magnet
in a solely compressive mode.  This technique completely eliminates
the potential for magnet breakage.

      Referring to the attached drawing, there is shown the magnet
(a) compressively held between two flanged hubs (b). The hubs have
thin "belleville"-shaped flexible flanges (b-1) which bear against
the ends of the magnet to provide the coupling to the magnet.  The
flanges are curved along lines corresponding to the deflection
characteristics of such "springs", and lie flat against the ends of
the magnet at the point of full compression.  In this configuration,
a maximum compressive force can be exerted with a minimum increase in
the rotor envelope.  The assembly view shows the design in relation
to existing frame members in the IBM 58 mm motor,...