US4998033A — Gas dynamic bearing for spindle motor

Claim 1

Independent Claim 169 words

A spindle motor comprising a stator including a support shaft positioned on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft and having an inner peripheral surface, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended outwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, said stator coil being secured to the outer peripheral portion of said support shaft above said radial bearing, and said rotor magnet member being secured to the inner peripheral surface of said rotor so that a radial gap is provided between said stator coil and said rotor magnet member.

Claim 2

Dependent Claim 169 words

A spindle motor comprising a stator including a support shaft positioned on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft and having an inner peripheral surface, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended outwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, said stator coil being secured to the outer peripheral portion of said support shaft above said radial bearing, and said rotor magnet member being secured to the inner peripheral surface of said rotor so that a radial gap is provided between said stator coil and said rotor magnet member.

Claim 3

Dependent Claim 166 words

A spindle motor comprising a stator including a support shaft stood on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended outwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, said stator coil being secured to the outer peripheral portion of said support shaft above said radial bearing, and said rotor magnet member being secured to the under side of a top of the cap-shaped rotor so that an axial gap is provided between said stator coil and said rotor magnet member.

Claim 4

Dependent Claim 166 words

A spindle motor comprising a stator including a support shaft stood on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended outwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, said stator coil being secured to the outer peripheral portion of said support shaft above said radial bearing, and said rotor magnet member being secured to the under side of a top of the cap-shaped rotor so that an axial gap is provided between said stator coil and said rotor magnet member.

Claim 5

Dependent Claim 130 words

A spindle motor comprising a stator including a support shaft stood on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended inwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, and both said stator coil and said rotor magnet member being disposed above said radial bearing.

Claim 6

Dependent Claim 130 words

A spindle motor comprising a stator including a support shaft stood on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended inwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, and both said stator coil and said rotor magnet member being disposed above said radial bearing.

Claim 7

Dependent Claim 41 words

A spindle motor according to claim 3, wherein said rotor magnet member is secured to the under side of a top of the cap-shaped rotor so that an axial gap is provided between said stator coil and said rotor magnet member.

Claim 8

Dependent Claim 138 words

A spindle motor comprising a stator including a support shaft positioned on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended outwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, and said rotor magnet member being secured to said rotor at a position which is inward of said movable piece of said thrust bearing.

Claim 9

Dependent Claim 138 words

A spindle motor comprising a stator including a support shaft positioned on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing comprising movable and fixed pieces, said movable piece being secured to the lower end of a cylindrical portion of said rotor and extended outwardly from said cylindrical portion, said fixed piece being secured to said base in opposing relation to said movable piece, and said rotor magnet member being secured to said rotor at a position which is inward of said movable piece of said thrust bearing.

Claim 10

Dependent Claim 31 words

A spindle motor according to claim 5, wherein said stator is secured to said base so that an axial gap is provided between said stator coil and said rotor magnet member.

Claim 11

Dependent Claim 37 words

A spindle motor according to claim 5, wherein said stator coil is secured to the lower part of said support shaft so that a radial gap is provided between said stator coil and said rotor magnet member.

Claim 12

Dependent Claim 93 words

A spindle motor comprising a stator including a support shaft positioned on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing being disposed above said radial bearing, and both said stator coil and said rotor magnet member being disposed below said radial bearing.

Claim 13

Dependent Claim 93 words

A spindle motor comprising a stator including a support shaft positioned on a base, a cap-shaped rotor rotatably and concentrically disposed around said support shaft, thrust and radial bearings disposed between said stator and said rotor, a stator coil secured to said stator, and a rotor magnet member secured to said rotor in opposing relation to said stator coil, wherein said thrust and radial bearings are hydrodynamic bearings, said thrust bearing being disposed above said radial bearing, and both said stator coil and said rotor magnet member being disposed below said radial bearing.

Claim 14

Dependent Claim 32 words

A spindle motor according to claim 8, wherein said stator coil is secured to said base so that an axial gap is provided between said stator coil and said rotor magnet member.

Claim 15

Dependent Claim 34 words

A spindle motor according to any one of claims 1 to 9, wherein said thrust bearing is preloaded by a magnetic force acting counter to a dynamic pressure acting in the direction of thrust.

Claim 16

Dependent Claim 70 words

A spindle motor according to any one of claims 1, 3, 5, 7, and 8, wherein the axial center of said rotor magnet member is offset from the axial center of said stator coil by a predetermined amount in the counter direction to the dynamic pressure generated from said thrust bearing, thereby preloading said thrust bearing in a counter direction to the dynamic pressure acting in the direction of thrust.

Claim 17

Dependent Claim 36 words

A spindle motor according to any one of claim 1 to 9, wherein said radial bearing is disposed so as to bear said rotor over a predetermined range including the center of gravity of said rotor.

Claim 18

Dependent Claim 29 words

A spindle motor according to any one of claims 1 to 9, wherein said fixed piece of said thrust bearing is secured to said stator through a resilient pad.

Claim 19

Dependent Claim 14 words

A spindle motor according ti claim 13, wherein said resilient pad is silicone rubber.

Claim 20

Dependent Claim 29 words

A spindle motor according to any one of claims 1 to 9, wherein said movable piece of said thrust bearing is secured to said rotor through a resilient pad.

Claim 21

Dependent Claim 14 words

A spindle motor according to claim 15, wherein said resilient pad is silicone rubber.

Claim 22

Dependent Claim 74 words

A spindle motor according to any one of claims 1 to 9, wherein the opposing annular sliding surfaces of said fixed and movable pieces of said thrust bearing are made of a ceramic material or made of a member coated with a kind of material different from the groundwork thereof or a member having a treated surface of degenerated groundwork thereof, and either of said sliding surfaces has spiral grooves for generating dynamic pressure.

Claim 23

Dependent Claim 17 words

A spindle motor according to claim 17, wherein said ceramic material is either silicon carbide or alumina.

Claim 24

Dependent Claim 76 words

A spindle motor according to any one of claims 1 to 9, wherein the opposing cylindrical sliding surfaces of said fixed and movable pieces of said radial bearing are made of a ceramic material material or made of a member coated with a kind of material different from the groundwork thereof or a member having a treated surface of degenerated groundwork thereof, and either of said cylindrical sliding surfaces has herringbone-shaped grooves for generating dynamic pressure.

Claim 25

Dependent Claim 17 words

A spindle motor according to claim 19, wherein said ceramic material is either silicon carbide or alumina.

Claim 26

Dependent Claim 43 words

A spindle motor according to any one of claims 1 to 4, 8 and 9, wherein some or all of said movable piece of said radial bearing, said rotor and said movable piece of said thrust bearing are arranged in an integral structure.

Claim 27

Dependent Claim 45 words

A spindle motor according to claim 21, either one or both of the moving pieces and the radial and thrust bearings in the integral structure are coated with a kind of material different from that of groundwork thereof, or the groundwork thereof is surface treated.

Claim 28

Dependent Claim 45 words

A spindle motor according to any one of claims 1, 2, 8 and 9, wherein some or all of said fixed piece of said radial bearing, said support shaft, said fixed piece of said thrust bearing and said base are arranged in an integral structure.

Claim 29

Dependent Claim 44 words

A spindle motor according to claim 23, either one or both of the fixed pieces of the radial and thrust bearings in the integral structure are coated with a kind of material different from that of groundwork thereof, or groundwork thereof is surface treated.

Claim 30

Dependent Claim 30 words

A spindle motor according to any one of claims 1 to 9, wherein said rotor has a support member adapted to hold hard disks on the outer peripheral surface thereof.

Claim 31

Dependent Claim 39 words

A spindle motor according to any one claims 1 to 9, wherein said support shaft is extended through a through-hole provided in the upper end portion of said rotor, and said support shaft being loosely fitted in said through-hole.

Claim 32

Dependent Claim 21 words

A spindle motor according to claim 26, wherein the distal end of said support shaft is secured to a stationary part.

Claim 33

Dependent Claim 28 words

A spindle motor according to any one of claims 1 to 9, wherein the upper end of said rotor is closed and not pierced by said support staff.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1994-03-04	1994-09-03	1995-03-05	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1998-03-04	1998-09-03	1999-03-05	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2002-03-04	2002-09-03	2003-03-05	$7700.00	Window Closed / Lapsed

Gas dynamic bearing for spindle motor

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag