Rock bit
US5485890A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1995 |
| Grant date | Jan 23, 1996 |
| Priority date | — |
| Expiry date | Apr 4, 2015 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/25
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A rock bit for drilling subterranean formations has an improved dynamic O-ring seal for retaining lubricant around the rock bit bearings during operation of the rock bit. Such a bit has a plurality of journal pins, each having a bearing surface, and a cutter cone mounted on each journal pin and including a bearing surface. A grease reservoir is in communication with such bearing surfaces for maintaining grease adjacent to the bearing surfaces. The grease is sealed in with dynamic O-ring seals rotating against a sealing surface with a Vickers hardness of at least 1000 and vibratory burnished to have a surface finish in the range of from 5 to 32 microinches AA. Preferably, the sealing surface is formed on a seal ring interposed between the cone and journal. Preferably the sealing surface comprises a tungsten carbide composite sprayed onto the outside surface of a steel ring which is then welded to a journal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.