US 5,357,163 AGranted

Motor with dynamic-pressure type bearing device

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsShinichi Minakuchi, Nobuhiro Yoshino

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Abstract

A motor having a dynamic-pressure type bearing device includes a cylindrical sleeve fixedly secured to a base, a shaft rotatably inserted into a hollow of the cylindrical sleeve, a hub fixedly secured to an end portion of the shaft, a ring-like rotor magnet fixedly secured to the hub, and an armature fixedly secured onto the base to be in opposed relation to the rotor magnet so as to constitute a motor driving device. Further, the motor has a disc-like plate coaxially and fixedly secured to an end portion of the shaft to have a diameter of the disc-like plate greater than a diameter of the shaft and a plate disposed in opposed relation to a surface of the disc-like plate. The bearing device includes a radial dynamic-pressure groove assembly having a predetermined groove configuration to generate a radial dynamic pressure in a radial direction of the shaft and an axial dynamic-pressure groove assembly having a predetermined groove configuration to generate an axial dynamic pressure in an axial direction of the shaft. The radial dynamic-pressure groove assembly is formed in at least one of an outer circumferential surface of the shaft and an inner surface of the cylindrical sleeve which face each other and the axial dynamic-pressure groove assembly is formed in at least one of the surface of the disc-like plate and a surface of the plate disposed in opposed relation to the surface of the disc-like plate.

Claims34

Dependent claims

A motor comprising:

a base;
a cylindrical member fixedly secured to said base;
a shaft rotatably inserted into a hollow of said cylindrical member;
a hub fixedly secured to an upper end portion of said shaft;
a ring-like rotor magnet fixedly secured to said hub;
an armature fixedly secured onto said base to be in opposed relation to said ring-like rotor magnet so as to construct motor drive means for driving said motor;
a disc-like plate coaxially and fixedly secured to a lower end portion of said shaft, a diameter of said disc-like plate being greater than a diameter of said shaft,
plate means disposed in opposed relation to a lower surface of said disc-like plate;
and
dynamic-pressure type bearing means comprising radial dynamic-pressure groove means having a predetermined groove configuration to generate a radial dynamic pressure in a radial direction of said shaft and axial dynamic-pressure groove means having a predetermined groove configuration to generate an axial dynamic pressure in an axial direction of said shaft, said radial dynamic pressure groove means being formed in at least one of an outer circumferential surface of said shaft and an inner surface of said cylindrical member which are in opposed relation to each other and said axial dynamic-pressure groove means being formed in at least one of said lower surface of said disc-like plate and a surface of said plate means disposed in opposed relation to said lower surface of said disc-like plate,
wherein said disc-like plate is encased in a cylindrical hole formed at a lower portion of said cylindrical member and a diameter of said cylindrical hole is determined so that a gap is formed between an inner circumferential surface of said cylindrical hole and an outer circumferential surface of said disc-like plate which are in opposed relation to each other, a thickness of said disc-like plate being determined so as to satisfy a condition of the thickness of said disc-like plate>said gap.times.20.

8 more elements

A motor comprising:

a base;
a shaft fixedly secured to said base;
a hub having at its center portion a cylindrical member, said shaft being inserted into a hollow of said cylindrical member so that said hub is rotatable;
a ring-like rotor magnet fixedly secured to said hub;
an armature fixedly secured onto said base to be in opposed relation to said ring-like rotor magnet so as to construct motor drive means for driving said motor;
a disc-like plate coaxially and fixedly secured to an upper end portion of said shaft, a diameter of said disc-like plate being greater than a diameter of said shaft;
plate means disposed in opposed relation to an upper surface of said disc-like plate;
and
dynamic-pressure type bearing means comprising radial dynamic-pressure groove means having a predetermined groove configuration to generate a radial dynamic pressure in a radial direction of said shaft and axial dynamic-pressure groove means having a predetermined groove configuration to generate an axial dynamic-pressure in an axial direction of said shaft, said radial dynamic pressure groove means being formed in at least one of an outer circumferential surface of said shaft and an inner surface of said cylindrical member which are in opposed relation to each other and said axial dynamic-pressure groove means being formed in at least one of said upper surface of said disc-like plate and a surface of said plate means disposed in opposed relation to said upper surface of said disc-like plate,
wherein said disc-like plate is encased in a cylindrical hole formed at an upper portion of said cylindrical member and a diameter of said cylindrical hole is determined so that a gap is formed between an inner circumferential surface of said cylindrical hole and an outer circumferential surface of said disc-like plate which are in opposed relation to each other, a thickness of said disc-like plate being determined so as to satisfy a condition of the thickness of said disc-like plate>said gap.times.20.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/057,388Filed 6 May 1993
Priority: JP 4-1156898 May 1992
Granted: 18 Oct 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

F16C 17/107
With grooves in the bearing surface to generate hydrodynamic pressure: with at least one surface for radial load and at least one surface for…
F16C 17/026
For radial load only: with helical grooves in the bearing surface to generate hydrodynamic pressure, e.g. herringbone grooves
F16C 17/045
For axial load only: with grooves in the bearing surface to generate hydrodynamic pressure, e.g. spiral groove thrust bearings
F16C 33/107
Details of distribution or circulation inside the bearings, e.g. details of the bearing surfaces to affect flow or pressure of the liquid: grooves…