RU2543824C1 - Rock drill bit - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: drill bit comprises legs with inclined pins with shifted in plan axes, installed on them conic rolling cutters with milled, casted or hard-alloy teeth located in parallel or at an angle to the generatrix of the rolling cutter, and flushing assembly. The size of slipping of rolling cutter teeth at which the maximum volume of drilled-out rock by each cutting structure tooth during the whole period of operating time of a bit is achieved, is pre-determined by relations depending on the mode of a braking or slipping, rolling cutter rim radius, a angle between two neighbouring teeth of a rolling cutter rim.

EFFECT: improving a bit operating efficiency.

3 dwg

Description

The invention relates to a rock cutting tool, and in particular to cone drill bits with milled, cast or carbide teeth for drilling, mainly soft rocks, not prone to rake formation.

Known drilling three-cone bit, including a housing, conical cones with milled teeth and flushing hydromonitor units located in the peripheral part of the inter-conical space (see IK Maslennikov, reference book "Drilling tool", M., Nedra, 1989, p. 36, Fig. 2.1.116).

The disadvantage of this bit is the relatively low efficiency of its work, which is associated with a suboptimal arrangement of cones and teeth on the conical surface of cones.

The closest to the proposed technical essence and the achieved result is a cone drill bit, including paws with inclined pins, conical cones mounted on them with milled, cast or carbide teeth, located at an angle to the cone, and a flushing unit (see RF patent No. 2473770, CL E21B 10/16, 2013).

This bit due to the use of paws with trunnions offset in the plan relative to the axis of the bit provides more effective destruction of rocks due to slipping of teeth relative to the surface of the face. To a certain extent, this is facilitated by the inclined position of the teeth relative to the cone forming cone. However, to obtain the maximum volume of damage to the face, it is necessary to know the angle of inclination of the teeth with respect to the generatrix of the cone, on the basis of which the optimal value of slippage is determined.

In connection with the stated technical result of the invention is to increase the efficiency of the drill bit by achieving the maximum volume of destructible rock with each tooth of the cone armament during the entire life of the bit.

The technical result is achieved by the fact that in the drill cone bit, which includes paws with inclined pins, conical cones mounted on them with milled, cast or carbide teeth located parallel or at an angle to the forming cone, and the flushing unit, according to the invention, the amount of tooth slippage cones - Δ, working respectively in the mode of braking and slipping, is determined by the formulas:

;

;

;

;

where R is the radius of the crown of the cone, mm;

β is the angle between two adjacent teeth of the crown of the cone, deg.

The invention is illustrated by drawings, where in Fig.1 shows a fragment of a General view of the bit, in Fig.2 is a view of the bit from the side of the working end; figure 3 - the trajectory of the vertex of the tooth during rotation of the cone.

Drill roller bit contains paws 1 (see FIGS. 1 and 2) with inclined pins 2, on which conical cones 3 with milled, cast or hard-alloy teeth 4 are mounted by bearings. In the bit body formed by welded paws 1, a flushing unit 5 is placed which, depending on the physicomechanical properties of the drilled rocks and the size of the bits, can be made in the form of one central nozzle or several hydraulic nozzles placed in the inter-cone openings. For effective destruction of soft rocks that are not prone to rake formation, cones 3 are installed with a displacement of the axes in the plan, as a rule, in the direction of rotation of the bit. In the proposed bit can be used and other layouts of cones. At the same time, cones 3 themselves can have both spur and helical armaments, which is determined primarily by the physicomechanical properties of the drilled rocks, as well as by creating favorable conditions for transporting the destroyed rock with flushing fluid to the annulus.

The principle of operation of the drill bit is as follows. When the bit is rotated, cones 3 roll over the surface of the face and destroy the rock under the influence of axial load and torque. The implementation of the bit with shifted cones 3 contributes to the efficiency of destruction of rocks due to slipping of the teeth. Moreover, the direction of slipping of the teeth on different crowns of the cones is different, while the slipping of the teeth in the direction of rotation of the cone is proposed to be called braking, and against the rotation of the cone - slipping (see figure 3). This figure shows the trajectory of the top of the tooth when rolling cones, namely: figure 3.1 shows the trajectory of the tooth during the slipping of weapons, figure 3.2 - with clean rolling and figure 3.3 - when braking weapons. In all figures, h is the magnitude of the maximum deepening of the tooth, mm; a V _CK is the sliding speed of the teeth of the weapon along the bottom of the well, m / s; ω is the angular speed of rotation of the cone, s ^-1 , and the entrance into contact with the face of the face of each subsequent tooth should be at the place of exit of the previous tooth.

The volume of the destroyed rock at each revolution of the bit depends on the amount of slippage - Δ of the cone teeth. In this case, the maximum volume of cuttings by each weapon of the weapon during the entire life of the bit, in the case of its weapons in the braking mode, is determined by the formula:

;

;

and during the operation of the cone armament in slip mode, the amount of slippage - Δ of the cone teeth, at which the maximum volume of cuttings is achieved in the same time, is determined by the following formula:

;

;

where R is the radius of the crown of the cone, mm;

β is the angle between two adjacent teeth of the crown of the cone, deg.

Destroyed rock is directed towards the periphery of the well and then into the annulus as armament cone and flushing fluid (the direction of flow is shown by arrows). There it is picked up by the flushing fluid and sent further to the inter-conical space, and from there to the annulus. From the annulus, sludge-rich flushing fluid is directed to the surface. This avoids the re-grinding of sludge and thereby reduce weapons wear and increase the mechanical drilling speed.

Thus, the proposed bit due to the use of optimal slippage provides a more effective destruction of the rock, improves the efficiency of the bit, namely to increase the penetration of the bit and the mechanical drilling speed while reducing the cost of drilling.

Claims (1)

A cone drill bit, including paws with inclined trunnions with axially displaced axes, conical cones mounted on them with milled, cast or carbide teeth parallel or at an angle to the forming cone, and a flushing unit, characterized in that the amount of cone teeth slippage, at which the maximum volume of cuttings is achieved with each tooth of the weapon during the entire life of the bit, respectively, in the braking and slipping mode, is determined by the formula:

;

,
where R is the radius of the cone of the cone, mm, β is the angle between two adjacent teeth of the cone of the cone, deg.

Images