Ball screw for vacuum apparatus
US5782135A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 4, 1997 |
| Grant date | Jul 21, 1998 |
| Priority date | — |
| Expiry date | Feb 4, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/18744
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A ball screw for a vacuum apparatus which includes a screw shaft having a spiral inner raceway formed on an outer peripheral surface thereof, a ball nut having a spiral outer raceway formed on an inner peripheral surface thereof, a plurality of balls disposed in a spiral space defined between the inner raceway and the outer raceway, and circulating members connecting ends of the spiral space to each other to define a continuous ball circulating passage. The plurality of balls are first balls formed of high polymer material containing polytetrafluoroethylene as a main component and second balls formed of either a metallic material or a ceramic material. The first balls circulate through the circulating passage together with the second balls. The second balls have lubricating films of crystalline polytetrafluoroethylene formed on the surface thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.