RU2435927C1 - Core drilling bit - Google Patents

Abstract

FIELD: mining. ^ SUBSTANCE: core drilling bit including housing with connection thread is divided with flushing ports into sectors which are equipped on end surface with cutters with hard-alloy plates. Flushing ports are located opposite at an angle in the sectors with well-forming cutting elements, i.e. forming the side surface of the well. Cutting elements are provided on the end surface with negative front angles to the surface of the bottom hole. Flushing ports located opposite at an angle increase removal intensity of well cuttings from the bottom hole, owing to which drilling speed increases. ^ EFFECT: self-sharpening of cutting elements and improvement of operating reliability and service life of drilling bit. ^ 2 dwg

Description

The invention relates to crowns intended for drilling wells with coring for fractured and alternating in hardness rocks during the exploration of deposits for solid minerals and water.

A diamond drill bit is known that contains a housing with a matrix divided by washing channels into sectors, in which the concentric rock cutting elements from the end surface are equipped with superhard composite material cutters mounted along the sectors arc and discretely in increments decreasing from the periphery to the center of the crown (RF Patent No. 2257458, published 02.20.05, IPC Е21В 10/48).

The disadvantage of this crown is the low penetration rate due to the cutting-abrasion method of rock destruction.

The closest to the proposed technical essence and the achieved result is a cutting type annular drill bit according to RF Patent 2359103, published on June 20, 2009, IPC Е21В 10/48, which contains a housing with a connecting thread, divided by washing channels into sectors that are equipped with end surfaces cutters reinforced with diamond carbide inserts and have negative rake angles in plan to the lateral internal and external cutting surfaces and negative rake angles to the end face of the face wells. The specified crown is selected as a prototype.

The disadvantage of this crown is the low penetration rate due to the cutting-abrasive method of rock destruction, as well as in the presence of flushing channels located at right angles, which does not contribute to upstream turbulence.

The objective of the invention is to increase the speed of penetration and resource of the crown due to the fact that the annular drill bit of the cutting type contains a housing with a connecting thread, divided by flushing channels into sectors, which are provided with carbide plates from the end surface having negative rake angles in relation to the side internal and external cutting surfaces and negative rake angles to the end surface of the bottom of the well, and the flushing channels are opposed at an angle.

Figure 1 shows a General view of the drill bit, side view, figure 2 is a view from the end surface.

The annular drill bit of the cutting type contains a housing 1 with a connecting thread, divided by flushing channels 2 into sectors 3, which are provided with cutters 5, 6 from the end surface 4, cutters 5, 6 are made in the form of sectors reinforced with diamond carbide plates, and have negative front angles β ₁ , β ₂ in terms of the lateral internal and external surfaces of the cutting and negative rake angles β _{3 of the} end surface of the bottom hole. The flushing channels 2 are counter-made at an angle α.

An annular drill bit operates as follows.

During rotation transmitted from the drill rig (not shown), the crown, when in contact with the bottom of the well, destroys it due to the fact that the leading cutting element 5, installed with a negative rake angle β ₃ , cuts a channel of depth h. The lagging cutting element 6, installed with negative rake angles β ₂ , β ₃ in the diametric plane, is processed core and the wall of the well, respectively. When cutting hard rocks, the wear of the cutting elements 5, 6 occurs, while the wear of the carbide base exceeds the wear of the diamond layer by a factor of tens, due to which a rake angle is formed and the cutter remains sharp and can continue to cut the rock with chip thickness h. However, the drilling speed depends, to a large extent, on the removal from the bottom of the borehole drill trifle (products of the destruction of the bottom). To increase the intensity of removal of the products of destruction from the bottom of the well, the flushing channels at the borehole cutting elements 5 are counter-angled, which is what the objective of the invention is achieved. The flushing fluid leaves the crown end, passes through the oncoming flushing channels, mixes, creating a turbulent flow, which is very important for increasing the mechanical drilling speed. The presence of a turbulent flow allows transporting larger particles of sludge to the surface, therefore, this sludge does not fall under the blade of the rock cutting tool for repeated destruction and, as a result, the mechanical drilling speed increases.

Claims (1)

An annular drill bit containing a body with a connecting thread, divided by flushing channels into sectors, which are provided with carbide inserts on the end surface having negative rake angles in plan to the lateral inner and outer cutting surfaces and negative rake angles to the bottom face of the well, characterized in that the washing channels are made at an angle at an angle.

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