Self-acting air bearing spindle for disk drive

A spindle assembly for use in a disk drive unit having a support base, said spindle assembly comprising:

• hollow hub means having an outer surface adapted to receive a stack of data storage disks and an interior volume;
• shaft means for rotatably supporting said hollow hub means, said shaft means including an elongated shaft, an inner cylindrical sleeve fitted around said shaft and concentric with it, said inner sleeve including a cylindrical outer surface defining an axial surface of said shaft means, first and second annular end plates of radial dimension exceeding the radial dimension of said inner sleeve, said first and second end plates fitted around said shaft and concentric with it at either ends of said inner sleeve, said radial surfaces of said shaft means being defined on said first and second end plates, and fastening means for holding said shaft, said inner sleeve, and the first and second end plates in a fixed relationship;
• said hollow hub means including a hollow rotatable hub, a hollow outer cylinder fixedly secured within said hollow hub, said outer cylinder including an inner cylindrical surface defining an axial surface of said hub means, said outer cylinder including first and second end surfaces, each defining one of two radial surfaces, and means for arranging said hub means in registration with said shaft means so that said radial and first and second axial surfaces of said outer cylinder are aligned respectively with said radial and first and second axial surfaces of said inner sleeve, and separated by small gaps;
• means for fixedly securing said shaft means to said support base;
• and
• bearing means defined within said volume and the axial and radial surfaces of said shaft means for creating air bearings between corresponding axial and radial surfaces of said hub means and said shaft means as said hub means rotates relative to said shaft means, said bearing means including a first herringbone groove pattern on said first radial surface of said first end plate, a second herringbone groove pattern on said second radial surface of said second end plate, and a double helical groove pattern on said axial surface of said inner sleeve, such that during rotation of said hub means, a journal air bearing develops between said double helical groove pattern surface and said axial surface of said outer cylinder and thrust air bearings develop between said first and second herringbone groove pattern surfaces and said first and second surfaces of said outer cylinder.