ROLLER CUTTER BIT Russian patent published in 1997 - IPC

FIELD: bore-hole drilling equipment. SUBSTANCE: rolling cutter bit has lug with journal which by means of radial and locking bearings carries rolling cutter with sealing unit in the form of bush interacting with end face of radial bearing. Sealing member interacts with outer surface of bush and surfaces of bore in rolling cutter and lug end interacting with sealing member. Surfaces of bush and bore are tapered, and taper angle of bush is 25-35 deg. which is by 15-20 deg. larger than taper angle of bore. Bush is made of antifriction material with modulus of elasticity which exceeds modulus of elasticity of sealing member material. Bush is installed with preliminary radial clearance of at least 0.1 mm. Major parameters of sealing unit are determined by analytic expression. EFFECT: high efficiency. 2 dwg