Drill bit for breaking rock by rotary cutting

Abstract

The invention discloses a drill bit for breaking rock by rotary cutting (a rotary cutting drill bit for short as follows), which comprises a drill bit main body, a roller cone, cutting teeth, an oil storage bag and a spray nozzle, wherein the drill bit main body comprises a roller cone shaft neck, a centralizing block, a high-pressure slurry channel and a connecting screw thread; and the roller cone and the shaft neck on the main body adopt a general bearing and a sealing structure of a tricone drill bit; a plurality of circles of cutting teeth are arranged from the large end to the small end of the roller cone; an included angle beta (an included angle of a cone body for short as follows) between a roller cone shaft neck plane on the main body and an axial line of the drill bit ranges from 0 to 90 degrees (containing beta i=beta(i+1) and beta i is not equal to beta(i+1)); the offset s (containing s i=s(i+1) and s i is not equal to s(i+1)) of the shaft neck ranges from-D / 2 to D / 2; i (greater than or equal to 1) represents a serial number of the roller cone; the included angle of the cone body corresponding to the cone i is represented by beta i; the offset of the shaft neck corresponding to the cone i is represented by s i; and D represents the diameter of the drill bit. According to the drill bit disclosed by the invention, an inner-row large gear ring is used for cutting the center of a shaft bottom and has high rock-breaking efficiency; each circle of cutting teeth can be used for scratching and cutting the shaft wall and has favorable effects for gauge protection and side drilling; the size of the shaft neck is large; the speed ratio of the cone body is smaller than 1; and the bearing has a long service life.

Description

technical field [0001] The invention belongs to the field of technical equipment such as oil and gas drilling engineering, mining, geological drilling, construction engineering, tunnel engineering, shield tunneling and non-excavation, and in particular relates to a rock-breaking drill bit in a rotary cutting mode. Background technique [0002] The drill bit is a tool that directly contacts the rock during the drilling process and breaks the rock through cutting and punching. The drill bits widely used in modern drilling engineering mainly include roller cone bits (including single cone bits and three cone bits) and PDC bits (Polycrystalline Diamond Compact Bits polycrystalline diamond compact bits). Today, both the roller cone bit and the PDC bit have been developed to a fairly high level, but there are still some insurmountable problems. One is fear of reaming and reaming, which will damage the roller cone bit of the sealed bearing, especially the PDC bit; the other is tha...

AI Technical Summary

Problems solved by technology

[0011] In view of the defects of the PDC bit, the present invention improves the roller cone bit and proposes a rock-breaking drill bit by rotary cutting, which solves the problem of low energy utilization rate, low rock breaking efficiency, short bearing life, and poor drilling efficiency of the existing double and triple cone bits. Low, and problems such as difficulty in chip removal and poor tooth wear resistance caused by the single-cone full-eye structure

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