Ball bearing assembly
US5344238A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 18, 1992 |
| Grant date | Sep 6, 1994 |
| Priority date | — |
| Expiry date | Dec 18, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S384/905
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
The ball bearing assembly has a total stroke range comprising a first portion where a clearance fit is applied and a second range where an interference fit is applied. The interference stroke range is used to, for example, carry a platform where precise alignment is necessary, and deflections or other movement of the platform must be minimized. Use of the ball bearing assembly to carry a platform holding a semiconductor wafer to be probed is illustrated. After each wafer is probed, the ball cage is reset such that any migration of the ball cage is eliminated so that the clearance and interference stroke ranges return to predetermined values. Further provided are means for rotationally resetting the ball cage, providing for even wear over the entire surfaces of the shaft and housing in their working zones to increase the useful lifetime of the assembly. Also provided are means for maintaining a predetermined interference fit over an extended temperature range, even where the shaft and housing operate at different temperatures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.