Multi-Piece Body Manufacturing Method Of Hybrid Bit

Abstract

A method of manufacturing a drill bit may include inserting an attachment end of a journal portion into a cavity of a blade portion. The journal portion includes the attachment end; a journal end opposite from the attachment end; and a journal on the journal end extending downward and radially outward from a longitudinal axis of the journal portion. The blade portion includes the cavity extending a distance into the blade portion; and at least one blade extending along the blade portion from adjacent to the cavity to a gauge region of the drill bit. Then, the method includes attaching the journal portion to the blade portion and mounting a roller cone to the journal.

What is claimed is: 
     
         1 . A method of manufacturing a drill bit, comprising:
 inserting an attachment end of a journal portion into a cavity of a blade portion,
 the journal portion comprising:
 the attachment end; 
 a journal end opposite from the attachment end; and 
 a journal on the journal end extending downward and radially outward from a longitudinal axis of the journal portion, and 
 
 the blade portion comprising:
 the cavity extending a distance into the blade portion; and 
 at least one blade extending along the blade portion from adjacent to the cavity to a gauge region of the drill bit; 
 
   attaching the journal portion to the blade portion; and   mounting a roller cone to the journal.   
     
     
         2 . The method of  claim 1 , wherein prior to inserting the journal portion into the cavity, the method further comprises disposing at least two o-rings around the attachment end, each two adjacent o-rings defining a lubrication section. 
     
     
         3 . The method of  claim 2 , wherein a lubrication channel extends from the lubrication section through the journal portion to the journal end. 
     
     
         4 . The method of  claim 2 , wherein the blade portion comprises a lubrication reservoir and a passageway extending from the lubrication reservoir to the cavity, and wherein upon attaching the journal portion to the blade portion, the passageway opens to the lubrication section. 
     
     
         5 . The method of  claim 1 , wherein attaching comprises inserting at least one locking pin through the blade portion and into the journal portion. 
     
     
         6 . The method of  claim 1 , wherein the blade portion is formed from a different material than the journal portion. 
     
     
         7 . The method of  claim 6 , wherein the journal portion is formed of a heat treatable steel. 
     
     
         8 . The method of  claim 6 , wherein the blade portion is formed of a matrix material. 
     
     
         9 . The method of  claim 1 , wherein the journal portion further comprises a locking segment formed by a plurality of intersecting outer side surfaces, the locking segment being between the attachment end and the journal end, and wherein upon inserting the journal portion into the cavity, the locking segment mates with a plurality of inner surfaces of the cavity. 
     
     
         10 . The method of  claim 1 , wherein the end of the at least one blade adjacent to the cavity is at a radial distance of 0 to 20% of the drill bit diameter from the cavity. 
     
     
         11 . The method of  claim 1 , further comprising disposing a center cutting element on the journal portion along the longitudinal axis of the journal portion. 
     
     
         12 . A method of manufacturing a drill bit, comprising:
 determining a primary torque transfer area between a journal portion and a blade portion of a multi-piece bit body; and   inserting an attachment end of the journal portion into a cavity of the blade portion to form the multi-piece bit body,
 the journal portion comprising:
 an attachment end; 
 a journal end opposite from the attachment end; 
 
   a journal on the journal end extending downward and radially outward from a longitudinal axis of the journal portion;
   a locking segment formed of a plurality of intersecting outer side surfaces around the journal portion, the locking segment being between the attachment end and the journal end, a total outer side surface area of the locking segment being equal to or greater than the primary torque transfer area, and   
 the blade portion comprising:
 the cavity extending a distance into the blade portion; and 
 a blade extending along the blade portion from adjacent to the cavity to a gauge region of the drill bit. 
 
   
     
     
         13 . The method of  claim 12 , further comprising inserting a locking pin through the blade portion and into the attachment end of the journal portion. 
     
     
         14 . The method of  claim 13 , further comprising determining a secondary torque transfer between the multi-piece bit body, wherein the secondary torque transfer is determined using the cross sectional area, the torque section radius, and the material yield strength of the locking pin to calculate a pin torque capacity of the locking pin. 
     
     
         15 . The method of  claim 12 , further comprising designing a weight-on-bit transfer plane, the weight-on-bit transfer plane comprising the contact area between a base surface of the locking segment and a mating surface of the cavity. 
     
     
         16 . The method of  claim 12 , wherein the locking segment is formed by machining the plurality of intersecting outer surfaces to fit within the cavity. 
     
     
         17 . The method of  claim 12 , wherein the journal portion comprises a ball hole, and the ball hole opens to a race surface of one of the journal. 
     
     
         18 . The method of  claim 12 , wherein the journal portion is formed of a different material than the blade portion. 
     
     
         19 . The method of  claim 12 , further comprising welding a threaded connection to the blade portion at an end opposite from the cavity. 
     
     
         20 . The method of  claim 12 , further comprising attaching a roller cone to the journal.