SU1668614A1 - Rotary-percussion drilling bit - Google Patents

Abstract

The invention relates to the mining industry and reduces the shear stresses acting on the central carbide bit inserts for percussion rotary drilling, by reducing the shear stresses in the material of these inserts from shock impulses. The bit includes a housing (K) 1 with peripheral and at least one central blind holes (GO) 3, made at its working end 2, inclined to the outer lateral surface K 1, and transverse through groove (P) 5. GO 3 carbide inserts 4 are installed. The depth P 5 exceeds the depth of the central GO 3, and its cavity communicates with the internal cavity of the central GO 3 in its corner zone nearest to the axis of the bit. In the course of drilling, the tangential component of the shock pulse acts on the central insert 4, which excites shear stresses in the body of this insert. The presence of P 5 provides the damping of K 1 in the direction of the tangential load due to the compliance of the wall between the center insert 4 and P 5, which leads to a decrease in shear stresses in the material of insert 4. 5 Il.

Description

ON O 00 O

The invention relates to the mining industry and can be used in drill bits for percussion rotary drilling.

The purpose of the invention is to reduce the loads acting on the central inserts of the bits by reducing the shear stresses in the material of the inserts from shock impulses.

1 shows a chisel for percussion rotary drilling, a general view (a variant with one central insert); figure 2 - the same (version with two central inserts); on fig.Z - view from the working end of the bit in figure 1 G in figure 4 - the same in figure 2; figure 5 is a diagram of the forces acting on the central insert.

The bit includes a housing 1 with a working end 2. At the working end, the peripheral and at least one central blind holes 3 are inclined to the outer side surface of the case, in which carbide inserts 4 are installed. At the working end 2 of case 1, a transverse through groove 5 is also made The depth of the groove 5 is greater than the depth of the central hole, and its cavity communicates with the internal cavity of this hole in its corner zone nearest the axis of the bit. In the presence of two central holes, the internal cavity of the groove 5 communicates with the internal cavities of both holes (Figures 2 and 4). .

Chisel works as follows. During the drilling process, shock loads and rotation are transmitted to it, under which carbide inserts 4 are fed into the rock and destroy it.

When interacting with the rock, the central inserts at the moment of impact are affected by the rock reaction P, which decomposes into the normal component N, acting along the axis of the insert, and the tangential component R, acting perpendicular to the axis of the insert. The tangential force R in the carbide insert 4 causes shear stresses that are most dangerous for the material of the insert. The presence at the working end 2 of the bit case 1 of the transverse through groove 5, the depth of which is somewhat greater than the depth of the central hole 3 under the insert 4, and the internal cavity communicates with the internal cavity of the hole in its corner area nearest the axis of the bit, provides damping of the case 1 in the direction of action - the social force R due to the compliance of the wall between the central insert 4 and the groove 5.

FIG. one

Claims (1)

In this case, the energy of the tangential force R goes to the generation of shear stresses in the body of the insert and the elastic deformation of the wall between the insert and the groove. As a result, the shear stresses in the central insert arising from the action of shock pulses are significantly reduced. All this allows to increase the durability of carbide inserts located in the central part of the bit body, as well as to increase the impact energy without increasing the diameter of the pin, which increases the speed of drilling. Invention Chisel for percussion rotary drilling, comprising a body, peripheral and at least one central blind holes, solid carbide inserts mounted in the holes, and a transverse groove made at the working end of the body, inclined to the outer lateral surface of the body; characterized in that, in order to reduce the loads acting on the central insert by reducing the shear stresses in the insert material from shock pulses, the transverse groove is a depth exceeding the depth of the central blind hole, wherein the cavity cavity communicates with the internal cavity of the central blind hole in its corner zone nearest the axis of the bit. 2 Fig.d FIG. four FIG. five