METHOD OF ASSEMBLY OF ROLLER-CUTTER DRILLING BIT BEARING (VERSIONS) Russian patent published in 1999 - IPC

FIELD: drilling equipment. SUBSTANCE: roller-cutter is installed on leg pin on radial journal bearings and secured with retaining bearing for rotation. Determined on roller-cutters is half of difference of diameters H of working surface of radial journal bearings, and measured on pins from lower side, in vertical plane, is distance h between projections on plane perpendicular to pin axis of working surfaces of same bearings. Then, roller-cutters and lugs are laid in order of increased of H and h and they are successively assembled beginning from part pair meeting the condition H-h ≤ ΔH_в, and finishing with parts pair meeting condition H-h ≥ ΔH_н, where ΔH_в and ΔH_н are positive and negative permissible values of ΔH. In case of manufacture of a lot of bits, exceeding 50 pieces, roller-cutters and legs are graded by size groups satisfying unequality ΔH_н ≤ H-h ≤ ΔH_в and within the size groups, random assembly is carried out. EFFECT: higher accuracy of assembly of bearings and, respectively, their stability due to limiting the angle of misalignment of roller cutter axis relative to pin axis in their working position within limits safe with respect to wear of journal bearings by seizing. 3 cl, 4 dwg