Drive motor for magnetic disks, optical disks, and magneto-optical disks

Abstract

A motor for rotating a magnetic disk, an optical disk, or a magneto-optical disk comprises an armature concentrically secured to a center shaft affixed to the base frame of a disk drive unit. A rotor frame is rotatably supported in a cantilever fashion on a free end of the center shaft by a pair of bearings. The rotor frame is cup-shaped with a depending cylindrical sidewall encircling the outer peripheral surface of the armature. The sidewall includes a disk support that projects outwardly from the sidewall. A permanent magnet secured inside the sidewall interacts with magnetic fields produced by the armature. The cantilever support makes it easier to bring armature leads through a hole in the mounting frame as a part of the manufacturing process. In an alternate embodiment, the center shaft is shortened so that the lower bearing on the shaft rests upon the frame. The cup-shaped rotor is mounted on the bearings with a hub having a depending cylindrical wall mounted on the lower bearing. The frame has an upstanding cylindrical wall encircling the depending cylindrical wall of the hub. The armature is mounted on the outer surface of the upstanding wall so that it encircles the lower bearing. This embodiment has a short axial length which produces a compact motor.

What is claimed is: .[. 
     
       1.  A motor, suitable for driving a magnetic disk, an optical disk, or a magneto-optical disk, which comprises: a. a frame having a planar bottom member;   b. an upstanding shaft on said planar bottom member, said upstanding shaft having a large diameter lower portion, an intermediate diameter middle portion and a small diameter upper portion;   c. an aperture in said planar bottom member;   d. a core mounted on said upstanding shaft on said middle portion and seated against said lower portion proximate said planar bottom member;   e. an armature wound on said core and energizable by receiving electrical energy from wires passing to said armature through said aperture;   f. a pair of spaced apart bearings mounted on said upstanding shaft on said upper portion above said armature;   g. a cup shaped rotor mounted on said bearings to allow said rotor to rotate about said upstanding shaft and armature, said rotor having a cylindrical open bottom encompassing said armature, and said rotor including disk support means for mounting a disk on said rotor in a plane perpendicular to the axis of said upstanding shaft; and   h. a plurality of permanent magnets mounted within said cup shaped rotor proximate to and spaced from said armature in magnetic engagement, whereby said rotor rotates about the upstanding shaft and armature when said armature is energized..]. .[.   
     
     
       2.  A motor according to claim 1 wherein said bearings are spaced apart by spring elements..]. .[.3. A motor according to claim 2 wherein said spring elements are Belleville springs..]. .[.4. A motor according to claim 1 
     
     
        wherein said bearings are spaced apart by an annular spacer..]. .[.5.  A motor according to claim 4 wherein said annular spacer is an annular ring..]. .[.6. A motor according to claim 5 wherein said annular ring comprises an annular segment..]. .[.7. A motor according to claim 5 wherein said annular ring comprises a plurality of annular segments..]. .[.8. A motor according to claim 4 wherein said annular spacer comprises an annular projection on the inside surface of said cup shaped rotor..]. .[.9. A motor according to claim 11 wherein said disk support means comprises an annular projection on the outside of said open bottom of the cup shaped rotor, and said annular projection has an upper surface in a plane perpendicular to the axis of said upstanding shaft..]. .[.10. A motor according to claim 9 wherein said rotor has a cylindrical outer surface above said annular projection, whereby a plurality of disks may be 
     
     
        mounted on said rotor..]. 11. A motor, suitable for driving a magnetic disk, an optical disk, or a magneto-optical disk, which comprises: a. a frame having a planar bottom member;   b. an upstanding shaft on said planar bottom member, said upstanding shaft including a lower portion having a central bore and a post having upper and lower portions, said post lower portion being secured within said central bore, and said post upper portion having an outer surface having two spaced apart circumferential recesses for providing bearing inner races;   c. an apertures in said planar bottom member;   d. upper and lower spaced apart bearings mounted on said post upper portion and in said recesses proximate said planar bottom member;   e. a cup shaped rotor having a central hub mounted on said bearings to allow said rotor to rotate about said upstanding shaft, said central hub including a depending cylindrical wall portion mounted on said lower bearing;   f. an upstanding cylindrical wall on said planar bottom member, spaced from and encircling said depending cylindrical wall portion of said rotor central hub;   g. a core mounted on the outside surface of said upstanding cylindrical wall;   h. an armature wound on said core and energizable by receiving electrical energy from wires passing to said armature through said aperture;   i. a depending outer cylindrical wall on said rotor, spaced from and encircling said armature; and,   j. .[.a plurality of.]. .Iadd.at least one .Iaddend.permanent .[.magnets.]. .Iadd.magnet .Iaddend.mounted on the inside surface of said rotor outer cylindrical wall proximate to and spaced from said armature in magnetic engagement, whereby said rotor rotates about said upstanding shaft and   
     
     
        armature when said armature is energized. 12. A motor, suitable for driving a magnetic disk, an optical disk, or a magneto-optical disk, which comprises: a. a frame having a planar bottom member;   b. an upstanding shaft on said planar bottom member, said upstanding shaft including a lower portion having a central bore and a post having upper and lower portions, and said post lower portion being secured within said central bore;   c. an aperture in said planar bottom member;   d. a core mounted on .Iadd.the outside surface of .Iaddend.said upstanding shaft lower portion proximate said planar bottom member;   e. an armature wound on said core and energizable by receiving electrical energy from wires passing to said armature through said aperture;   f. a pair of spaced apart bearings mounted on said post upper portion .Iadd.at least partially .Iaddend.above said armature;   g. a cup shaped rotor mounted on said bearings to allow said rotor to rotate about said upstanding shaft and armature, said rotor having a cylindrical open bottom encompassing said armature, and said rotor including disk support means for mounting a disk on said rotor in a plane perpendicular to the axis of said upstanding shaft; and   h. .[.a plurality of.]. .Iadd.at least one .Iaddend.permanent .[.magnets.]. .Iadd.magnet .Iaddend.mounted within said cup shaped rotor proximate to and spaced from said armature in magnetic engagement, whereby said rotor rotates about the upstanding shaft and armature when said armature is   
     
     
        energized. 13. A motor according to claim 12 wherein said post upper portion has a diameter greater than said post lower portion and said post 
     
     
        upper portion is seated against the end of said shaft lower portion. 14. A motor according to claim 12 wherein said post upper portion has an outer surface having recesses providing the inner races of said bearings. .[.15. A motor according to claim 1 wherein said aperture is located proximate said upstanding shaft..]. .[.16. A motor according to claim 1 wherein said permanent magnets are disposed angularly on an inside surface of said rotor so as to present alternate north and south poles in magnetic engagement with said armature..]. .[.17. A motor according to claim 1 including at least one side wall in the shape of a segment of a hollow cylinder..]. .[.18. A motor, suitable for driving a magnetic disk, an optical disk, or a magneto-optical disk, which comprises: a. a frame having a planar bottom member;   b. an upstanding shaft on said planar bottom member, said upstanding shaft including a lower portion having a central bore and a post having upper and lower portions, said post upper portion having a diameter greater than said post lower portion, said post lower portion being secured within said central bore, and said post upper portion being seated against the end of said shaft lower portion;   c. an aperture in said planar bottom member;   d. upper and lower spaced apart bearings mounted on said post upper portion proximate said planar bottom member;   e. a cup shaped rotor having a central hub mounted on said bearings to allow said rotor to rotate about said upstanding shaft, said central hub including a depending cylindrical wall portion mounted on said lower bearing;   f. an upstanding cylindrical wall on said planar bottom member, spaced from and encircling said depending cylindrical wall portion of said rotor central hub;   g. a core mounted on the outside surface of said upstanding cylindrical wall;   h. an armature wound on said core and energizable by receiving electrical energy from wires passing to said armature through said aperture;   i. a depending outer cylindrical wall on said rotor, spaced from and encircling said armature; and,   j. a plurality of permanent magnets mounted on the inside surface of said rotor outer cylindrical wall proximate to and spaced from said armature in magnetic engagement, whereby said rotor rotates about said upstanding shaft and armature when said armature is energized..]. .[.19. A motor according to claim 18 wherein said bearings are spaced apart by spring elements..]. .[.20. A motor according to claim 19 wherein said spring elements are Belleville springs..]. .[.21. A motor according to claim 18 wherein said bearings are spaced apart by an annular spacer..]. .[.22. A motor according to claim 21 wherein said annular spacer is an annular ring..]. .[.23. A motor according to claim 22 wherein said annular ring comprises an annular segment..]. .[.24. A motor according to claim 22 wherein said annular ring comprises a plurality of annular segments..]. .[.25. A motor according to claim 21 wherein said annular spacer comprises an annular projection on the inside surface of said rotor central hub..]. .[.26. A motor according to claim 18 wherein said cup shaped rotor includes disk support means for mounting a disk on said rotor in a plane perpendicular to the axis of said upstanding shaft..]. .[.27. A motor according to claim 1 wherein said aperture is located proximate said armature..]. .[.28. The motor of claim 1 wherein said permanent magnets are disposed angularly on the inside surface of said rotor so as to present alternate north and south poles in magnetic engagement with said   
     
     
        armature..]. 29. A motor according to claim 11 wherein said cup shaped rotor includes disk support means for mounting a disk on said rotor in a 
     
     
        plane perpendicular to the axis of said upstanding shaft. 30. A motor according to claim 11 wherein said aperture is located proximate said armature. .[.31. The motor of claim 11 wherein said permanent magnets are disposed angularly on the inside surface of said rotor so as to present alternate north and south poles in magnetic engagement with said 
     
     
        armature..]. 32. A motor according to claim 12 wherein said bearings are 
     
     
        spaced apart by spring elements. 33. A motor according to claim 32 wherein 
     
     
        said spring elements are Belleville springs. 34. A motor according to 
     
     
        claim 12 wherein said bearings are spaced apart by an annular spacer. 35. A motor according to claim 34 wherein said annular spacer is an 
     
     
        annular ring. 36. A motor according to claim 35 wherein said annular ring 
     
     
        comprises an annular segment. 37. A motor according to claim 35 wherein 
     
     
        said annular ring comprises a plurality of annular segments. 38. A motor according to claim 34 wherein said annular spacer comprises an annular 
     
     
        projection on the inside surface of said cup shaped rotor. 39. A motor according to claim 12 wherein said disk support means comprises an annular projection on the outside of said open bottom of the cup shaped rotor, and said annular projection has an upper surface in a plane perpendicular to 
     
     
        the axis of said upstanding shaft. 40. A motor according to claim 39 wherein said rotor has a cylindrical outer surface above said annular projection, whereby a plurality of disks may be mounted on said rotor. 
     
     
            A motor according to claim 12 wherein said aperture is located 
     
     
        proximate said upstanding shaft. 42. A motor according to claim 12 wherein .[.said.]. .Iadd.a plurality of .Iaddend.permanent magnets are disposed angularly on an inside surface of said rotor so as to present alternate 
     
     
        north and south poles in magnetic engagement with said armature. 43. A motor according to claim 12 including at least one side wall in the shape 
     
     
        of a segment of a hollow cylinder. 44. A motor according to claim 11 
     
     
        wherein said bearings are spaced apart by spring elements. 45. A motor according to claim 44 wherein said spring elements are Belleville springs. 
     
     
        6. A motor according to claim 11 wherein said bearings are spaced apart by 
     
     
        an annular spacer. 47. A motor according to claim 46 wherein said annular 
     
     
        spacer is an annular ring. 48. A motor according to claim 47 wherein said 
     
     
        annular ring comprises an annular segment. 49. A motor according to claim 47 wherein said annular ring comprises a plurality of annular segments. 
     
     
            A motor according to claim 46 wherein said annular spacer comprises an annular projection on the inside surface of said rotor central hub. .Iadd.51. A motor, suitable for driving a magnetic disk, an optical disk, or a magneto-optical disk which comprises: a. a frame having a planar bottom member;   b. an upstanding shaft including a lower portion mounted to said planar bottom member and an upper portion projecting upwardly therefrom;   c. an aperture in said planar bottom member;   d. upper and lower spaced apart bearings mounted on said shaft upper portion proximate said planar bottom member;   e. a cup shaped rotor having a central hub mounted on said bearing to allow said rotor to rotate about said upstanding shaft, said central hub including a depending cylindrical wall portion mounted on said lower bearing and disk support means for mounting a disk on said rotor in a plane perpendicular to the axis of the upstanding shaft;   f. an upstanding cylindrical wall on said planar bottom member, spaced from and encircling said depending cylindrical wall portion of said rotor central hub;   g. a core mounted on the outside surface of said upstanding cylindrical wall;   h. an armature wound on said core and energizable by receiving electrical energy from wires passing to said armature through said aperture;   i. a depending outer cylindrical wall on said rotor, spaced from and encircling said armature;   j. the inner diameter of said disk support means being greater than the outer diameter of the depending cylindrical wall portion and less than the outer diameter of the depending outer cylindrical wall;   k. at least one permanent magnet mounted on the inside surface of said rotor outer cylindrical wall and the armature are positioned at a level lower than the disk support means and said permanent magnet being proximate to and spaced from said armature in magnetic engagement, whereby said rotor rotates about said upstanding shaft and armature when said armature is energized. .Iaddend. .Iadd.52. A motor according to claim 51 wherein the planar bottom member is provided with a bore, and wherein the lower portion of the shaft is secured therewithin. .Iaddend. .Iadd.53. A motor according to claim 52 wherein said planar bottom member is provided with an annular axially upwardly projecting portion about said bore, and wherein said upstanding cylindrical wall projects upwardly therefrom. .Iaddend. .Iadd.54. A motor according to claim 51 wherein the armature and bearings are at least in partial overlapping axial relationship. .Iaddend.