US 4,655,616 AGranted

Computer direct disc drive with magnetically stabilized shaft

AssigneeMagtrol, Inc.

InventorJohn E. Ducan

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Abstract

A computer direct disc drive wherein a hub is mounted on a shaft supported in spaced bearings within a housing with one of the bearings being fixed and the other bearing having an outer race which is free to float both radially and axially and wherein a biasing spring arrangement and a preload sleeve is positioned around the shaft to bias the outer race of the floating bearing away from the fixed bearing, the improvement which consists mounting magnets within the preload sleeve in axially spaced relationship to each other and in radially spaced relationship to the shaft to set up a magnetic circuit through the shaft, preload sleeve and housing to bias the shaft toward the magnets and force the outer race of the floating bearing into engagement with the housing to thereby stabilize it against radial movement while still permitting it to move axially to compensate for thermal variations to which the direct disc drive is subjected. In another embodiment, disc springs are located between the housing and the outer race, and the magnets are mounted on the housing.

Claims16

Dependent claims

In a computer disc direct drive having a hub, a shaft fixedly mounting said hub, a housing, a first bearing having a first outer race fixedly mounted in said housing and a first inner race fixedly mounting said shaft, a second bearing having a second inner race fixedly mounted on said shaft in axially spaced relation to said first inner race and having a second outer race, a first clearance between said second outer race and said housing, spring means effectively positioned between said housing and said shaft for transmitting a biasing force to said second outer race, the improvement for maintaining the axis of rotation of said shaft stable comprising magnet means, means for fixedly mounting said magnet means relative to said housing in contiguous spaced relationship to said shaft, a second clearance between said magnet means and said shaft which is greater than said first clearance, said magnet means producing a magnetic circuit with said shaft and said housing to thereby bias said shaft in a radial direction in the area of said second bearing to thereby cause a portion of said second outer race to abut said housing while said shaft does not contact said magnet means to thereby take up play between said shaft and said housing.

Dependencies are inferred from the claim text.