Floyd R Scott

US Patent:

46130020, Sep 23, 1986

Filed:

Apr 30, 1984

Appl. No.:

6/605536

Inventors:

Paul R. Pittman - Round Rock TX
Floyd L. Scott - Austin TX
William R. Hamilton - Austin TX

Assignee:

Hughes Tool Company - Houston TX

International Classification:

E21B 402

US Classification:

175107

Abstract:

A downhole drilling tool having a tubular stem connected to the drill string, and a tubular housing mounted concentrically and rotatably on the stem, forming an annular space between the housing and the stem. A plurality of bearings within the annular space support the housing against radial and longitudinal thrust loads. A plurality of seals within the annular space above and below the bearings form a lubricant chamber. The housing has a cylindrical lubricant passage extending between the lubricant chamber and the annular space outside of the lubricant chamber. A cylindrical piston is sealably slidable within the lubricant passage and responds to pressure of the drilling fluid entering the passage from the exterior of the housing to force lubricant out of the passage and into the lubricant chamber in order to replace lubricant which is lost therefrom. A downhole drilling motor is attached to the lower end of the housing. The drilling motor has a stator and a rotor which is rotated with respect to the stator in response to the flow drilling fluid through the drilling motor.