Electric motor having a stator and a rotor
US5714828A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1995 |
| Grant date | Feb 3, 1998 |
| Priority date | — |
| Expiry date | Mar 2, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K3/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An improved spindle motor, particularly for a hard-disc drive, having a stator in the form of a cylindrical coil carried by a mounting plate and a permanent magnet rotor carried on a rotatable hub. At its outer circumference the rotor generates a field perpendicular to the axis of rotation. A bell-shaped portion of the hub surrounds the coil. The hub is supported on the motor shaft by axial and radial hydrodynamic bearings. A soft-iron sleeve-shaped yoke externally surrounds the coil configuration. This permits the coil to be free of soft-magnetic parts, thereby reducing its inductance and improving the dynamic drive characteristics of the motor. The coil is preferably formed by curved foil windings, so there are no winding slots. This avoids the production of detent torques.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.