Stepped spindle motor shaft to reduce disk drive acoustic noise
US5625511A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1995 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Jan 11, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16C2370/12
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A spindle motor shaft having variable geometrical features for adjusting the torsion mode frequency of the shaft/stator assembly. The variable geometric features allow the torsion mode frequency to be tuned away from the driving force frequency of the motor. Variable geometrical features for the shaft may include circumferential grooves, radial slots cut through the shaft, or transverse holes disposed along the axis of the shaft. The radial slots have a longitudinal axis that is parallel to the axis of the shaft. Where circumferential grooves are used, the circumferential grooves may be designed to form a locator region along the shaft axis to promote axial alignment of the shaft and stator. Thermal track-misregistration (TMR) or screw torque problems are not introduced in the process of reducing or eliminating the acoustic problem thereby establishing a torsion mode frequency which is not subject to change due to temperature or time. Further, the removal of material from the shaft reduces the torsional stiffness of the shaft and lowers the torsion mode frequency of the shaft. Finally, the use of circumferential grooves prevents the wicking of excess epoxy up the shaft by the movem…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.