Roller Cone Bit Bearing, and Bearing Materials

Abstract

A journal bearing element for use in forming a roller cone bit coupled to a bearing shaft to prevent circumferential sliding. Also included are material compositions of the journal bearing element. A journal bearing element is fixed in place relative to a head section and comprised of dense high purity powdered metal alloys with uniform micro-structure. A preferred material is comprised of a metal made of a carbon content of about 2.3% by weight, chromium of about 14% by weight, vanadium of about 9% by weight, and molybdenum at about 1% by weight.

1 . An earth boring bit comprising:
 a bit body;   a leg section depending from the body;   a bearing shaft extending from the leg having a circular bearing surface having an indentation formed substantially aligned with the axis of the bearing shaft;   a coupling element disposed in the indentation;   a journal bearing element on the bearing shaft and joined to the coupling element thereby coupling the journal bearing element to the bearing shaft.   
   
   
       2 . The earth boring bit of  claim 1 , wherein the coupling element comprises a raised profile formed on the journal bearing element inner surface and a corresponding indentation in the bearing shaft formed to receive the raised profile therein for coupling engagement between the journal bearing and the bearing shaft. 
   
   
       3 . The earth boring bit of  claim 1 , wherein the indentation comprises a first channel formed in the bearing shaft surface, the coupling element comprises a key member extending from the first channel into a second channel formed in the inner surface of the journal bearing element. 
   
   
       4 . The earth boring bit of  claim 1 , wherein the journal bearing element comprises at least two separate members disposed on the bearing shaft. 
   
   
       5 . The earth boring bit of  claim 4 , wherein the members substantially circumscribe the bearing shaft circumference. 
   
   
       6 . The earth boring bit of  claim 5 , wherein one of the journal bearing elements is coupled with a coupling element thereby preventing circumferential movement of each bearing member with respect to the bearing surface. 
   
   
       7 . The earth boring bit of  claim 1  further comprising a cone mounted for rotation on the bearing shaft, the cone including a mating bearing surface for engagement with the journal bearing element outer surface. 
   
   
       8 . The earth boring bit of  claim 1 , wherein coupling the journal bearing element to the bearing shaft prevents circumferential sliding of the journal bearing element around the bearing shaft. 
   
   
       9 . An earth boring bit comprising:
 a bit body;   a leg section depending from the body;   a bearing shaft extending from the leg having a circular bearing surface; and   a journal bearing element formed separately from the bit and adhered to the bearing shaft.   
   
   
       10 . The earth boring bit of  claim 9 , wherein the journal bearing element is adhered to the bearing shaft by a process selected from the group consisting of soldering, brazing, and gluing. 
   
   
       11 . The earth boring bit of  claim 9 , wherein the journal bearing element comprises at least two separate members disposed on the bearing shaft. 
   
   
       12 . The earth boring bit of  claim 11 , wherein the members substantially circumscribe the bearing shaft circumference. 
   
   
       13 . The earth boring bit of  claim 12 , wherein one of the journal bearing elements adhered to the bearing shaft prevents circumferential movement of each of the other bearing members. 
   
   
       14 . The earth boring bit of  claim 9  further comprising a cone mounted for rotation on the bearing shaft, the cone including a mating bearing surface for engagement with the journal bearing element outer surface. 
   
   
       15 . The earth boring bit of  claim 9 , wherein adhering the journal bearing element to the bearing shaft prevents circumferential sliding of the journal bearing element around the bearing shaft. 
   
   
       16 . An earth boring bit comprising:
 a bit body;   a leg section depending from the body;   a bearing shaft extending from the leg having a circular bearing surface; and   a journal bearing element comprising an alloy, wherein the alloy includes at least about 3% by weight of vanadium.   
   
   
       17 . The earth boring bit of  claim 16  wherein the alloy is formed from a stainless steel powder. 
   
   
       18 . The earth boring bit of  claim 16  wherein the vanadium content exceeds about 6% by weight of the alloy. 
   
   
       19 . The earth boring bit of  claim 16  wherein the vanadium content is at least about 9% by weight of the alloy. 
   
   
       20 . The earth boring bit of  claim 16  wherein the alloy comprises carbon with a content of about 2.3% by weight of the alloy, chromium with a content of about 14% by weight of the alloy, vanadium with a content of about 9% by weight of the alloy, and molybdenum with a content of about 1% by weight of the alloy.