Bearing assembly for a drill bit

Abstract

The cutter joint is formed on a trunnion by a peripheral radial-trust rolling bearing whose internal ring ( 4 ) together with rolling bodies ( 6 ) and a cage ( 7 ) are arranged on the trunnion ( 2 ) and locked thereon by snap ring ( 15 ), an external bearing ring ( 5 ) is inserted into the cutter ( 3 ) and locked therein by a circlip ( 12 ). The end radial-trust rolling bearing comprises an external ring ( 9 ) inserted into the cutter and internal ring ( 8 ) which is arranged on the trunnion together with rolling bodies ( 10 ) and cage ( 11 ) in such a way that it is slidable and trusted to the trunnion through a spring ( 16 ). In one embodiment, the inventive bearing assembly comprises a trust needle bearing arranged between the cutter and the trunnion through an axial spring. Said invention makes it possible to remove sliding friction between the adjacent rolling bodies in bearings, reduce heat generation in a bearing chamber, limit the deviation of rollers in conical bearings from a linear contact with bearing races, automatically remove bearing plays, thereby excluding heat blocking during a bit operation. The invention also simplifies the process of production of the drill bit, makes it possible to carry out non-destructive tearing of the cutter and to reuse the arm thereof. The technical result of the invention increases the service life of the bearing assembly, increases load applied to the drilling bit and rotating velocity thereof, thereby increasing drilling speed and drilling rate for a bit.

1 - 8 . (canceled)  
     
     
         9 . A bearing assembly for a drill bit comprising: 
 at least one foot with a trunnion;    a roller cutter;    a radial-thrust roller bearing, locking said roller cutter on said bearing support by means of a spread piece in the axial gap between said trunnion and the component, inserted into and fixed to said roller cutter on the side of the trunnion base;    an end bearing; and    wherein said radial-thrust roller bearing, locking said roller cutter on said trunnion, is executed in the form of a separate internal ring and a separate external ring with bearing races, and rolling bodies corresponding to them.    
     
     
         10 . The bearing assembly as set forth in  claim 9 , wherein said radial-thrust roller bearing, locking the roller cutter on the trunnion, executed in the form of a separate internal ring and a separate external ring with bearing races, and rolling bodies corresponding to them, is provided with a cage.  
     
     
         11 . The bearing assembly as set forth in  claim 9 , wherein said end bearing is executed in the form of a separate internal ring and a separate external ring with bearing races, and cylindrical rollers between them.  
     
     
         12 . The bearing assembly as set forth in  claim 9 , wherein said end bearing is executed in the form of a radial-thrust conical roller bearing, comprising a separate internal ring and a separate external ring with bearing races, and rolling bodies corresponding to them, united by a cage, the internal ring of the said end bearing being fitted on the trunnion with a possibility of free movement along the trunnion, and with an axial rest of the said ring against the trunnion through a spring, e.g. a disk-type spring.  
     
     
         13 . The bearing assembly as set forth in  claim 9  further comprising a thrust bearing between said roller cutter and said trunnion, executed in the form of a pair of supporting rings, with a cage having rolling bodies located between them, moreover, the said bearing resting against said trunnion end through a spring, e.g. a disk-type spring.  
     
     
         14 . The bearing assembly as set forth in  claim 9 , wherein said bearing, nearest to the trunnion base, is located inside the above component, inserted into and fixed to the roller cutter on the side of the trunnion base, the said component being screwed into the roller cutter on the side of the trunnion base to a rest of the radial-thrust bearing against the trunnion.  
     
     
         15 . The bearing assembly as set forth in  claim 9 , wherein said component, inserted into and fixed to the roller cutter on the side of the trunnion base, is executed in the form of a split spring ring.