RU2355863C2 - Bore cone bit - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention refers to equipment of rock destroying tool, particularly to hard-alloy teeth designed for equipment of bore bits. The bore bit consists of one or more sections with a leg, and of a roller cutter movably secured on the leg and equipped with hard-alloy teeth with cylinder tails and a working rock-destroying head in form of converging on a rounded top crests. A pyramidal working head in sections below the rounded top has a shape of trapezium with rounded angles. Radius of rounding of the top of the working head of the tooth is bigger or equal to product of one sixteenth of diametre of a cylinder part of the tooth and number of facets of trapezium working head of the tooth and is bigger or equal to radius of rounding of ribs of the working head of the tooth. The teeth are arranged on crowns in the case of a roller cutter where relative to the direction of the roller cutter rotation a bigger side of pyramid base is oriented on trailing edge and smaller side is oriented on entering edge.

EFFECT: increased efficiency of bore bit operation due to increased efficiency of operation of hard-alloy rock destroying teeth.

2 cl, 8 dwg

Description

The invention relates to the arming of a rock cutting tool, namely to carbide teeth intended to equip drill bits.

Known drill bit [1], taken as an analogue, with carbide teeth for weapons cones having a rock-cutting surface in the form of two or more mutually converging blades.

The advantage of such carbide teeth is that the working head of the tooth in the form of two or more converging blades allows you to create on the face surface a network of intersecting, close to vertical, cracks under each blade and a large number of alternating and unconnected small protrusions and troughs. If we take the force to crush a certain volume of rock for 100%, then the force during lateral shear of the same volume of rock is only 11%. Therefore, wedge-shaped blades when shifting by the wedge surface of small protrusions towards the depressions spend an order of magnitude less effort to destroy them.

The lack of teeth with a rock-cutting surface in the form of two or more converging blades can be attributed to the insufficient resistance of the teeth, due to the fact that the destructible rock, falling into the space between adjacent blades, has a wedging effect, tearing one blade from the other. As is known, hard alloys have high resistance to compression deformations and insufficient tensile strength.

Also known is a drill bit [2], taken as a prototype, in which the wedging effect of the rock in the space between the blades of the teeth is significantly reduced.

At this bit, the working head of the carbide tooth is represented by the on-going and run-off sides in the form of a wedge surface each, whose edges are located in the plane of symmetry of the tooth and are inclined to its axis at unequal angles. By increasing the strength of the specified clove increases the efficiency of the drilling process. The pointed apex of such a tooth provides a high specific pressure on the rock, significantly exceeding the pressure exerted on the rock by other teeth, in particular teeth with spherical or wedge-shaped rock-breaking surfaces. However, this tooth also has a limited scope (hard rock drilling) and a technological disadvantage, which consists in the need for careful orientation of the teeth when assembling them on the roller cutter sections. However, the resistance of the pointed tip of such a clove when tested on a bench with a cyclic shock loaded is too low.

The technical result of the present invention is to increase the durability and performance of weapons of the drill bit.

,The technical result is achieved by the fact that in the drill cone bit, which includes one or more sections with a paw, a roller cone movably fixed on it, equipped with carbide teeth with cylindrical shanks and a working rock cutting head in the form of ridges converging on a rounded apex, according to the invention, a pyramidal working head in sections below the vertex rounding, it has the form of a trapezoid with rounded corners, and the radii of the rounding of the top and ribs are connected by the following relation with the diameter of the cylindrical h part of the clove and the number of faces of the pyramid:

,

where: r ₁ is the radius of rounding of the top of the working head of the tooth, mm;

r ₂ is the radius of rounding of the ribs of the working head of the tooth, mm;

d is the diameter of the cylindrical part of the tooth, mm;

n is the number of faces of the pyramidal working head of the tooth.

Tungsten carbide teeth are located on the crowns in the cone of the cone with the orientation of the large side of the base of the pyramid on the reeling side and the small side on the free side relative to the direction of rotation of the cone.

This form of rock-cutting clove with its specified orientation relative to the direction of rotation of the cone allows you to avoid wedging effects on the blade of the clove, characteristic of the analogue, and at the same time significantly increase the durability of the armament of the bit by reinforcing the runaway side of the clove like a prototype. When teeth are introduced into the bottom rock, the lateral rounded peaks of the ridges exert a bursting effect on the walls of the holes formed under the teeth, intensifying the well drilling process.

Thus, an increase in the working efficiency of the tooth occurs due to the structural design of the working head, which provides the necessary strength of the rock cutting part, and where, when introduced into the rock, the forces acting on the arms of the bit are redistributed from uniform in a spherical section to alternating in faces and rounded edges of the pyramid by changing the geometric shape of the section from a circle to a polygon with rounded corners.

The list of figures drawings. Figure 1, 2, 3 shows the proposed carbide tooth in three projections, figure 1 is the main view of the tooth, figure 3 is a top view of the working head of the tooth, figure 2 is a side view of the tooth. Figure 4 shows a section 4-4 along the cylindrical part of the clove and the edge of the working head of figure 3. Figure 5 shows a clove with secant planes; Fig.6 is a section 1-1, Fig.7 is a section 2-2, Fig.8 is a section 3-3. All three sections are shown in enlarged view.

Figure 5 shows the main view of the proposed carbide tooth. Figure 6 (section 1-1 of figure 5) shows a diagram of the direction of action of rock cutting forces when introducing the head working spherical part of the clove into the rock being drilled. There is a circular uniform contact of the carbide tooth with the rock, the rock breaking forces have a uniform distribution (shown by arrows), the crushed rock is crushed with the formation of relatively small particles of cuttings.

In Fig. 7 and Fig. 8, the arrows schematically show the direction and magnitude of the actual destructive forces when changing the geometric shape of the cross sections of the working head of the tooth from the circle (Fig. 6) to a polygon with rounded corners. The specific pressure exerted on the rock by the edges of the pyramid is significantly higher than its faces, the zone of volumetric destruction of the rock by the hard-alloyed tooth increases, thereby increasing the drilling efficiency with the formation of larger particles of cuttings.

The advantage of the proposed drill bit, equipped with carbide rock cutting teeth with a working head in the form of a pyramid with rounded ribs having the radii of rounding of the top and ribs associated with the above ratio with the diameter of the tooth and the number of faces of the pyramid, is increased strength and aggressiveness of the working head. This allows for the destruction of strong rocks and to create a high specific pressure of the drill bit at the bottom of the well, thereby providing an increased mechanical drilling speed due to an increase in the volumetric fracture zone and the formation of large particles of drill cuttings with a reduction in dust generation during drilling of wells in mining pits and workings.

The results of bench tests of drill bits with the proposed weapons confirm its high durability and mechanical drilling speed.

Information sources

1. Copyright certificate No. B 1852 (not subject to publication in the open press) dated 10/04/1966, “Drill bit”, MPK ЕВВ 23/20 (analogue).

2. RF patent No. 1677230 of September 15, 1991, Bull. No. 34, "Carbide tooth for drill bits", IPC 5 ЕВВ 10/16 (prototype).

Claims (2)

1. Drill cone bit, including one or more sections with a paw, a roller cone movably fixed on it, equipped with carbide teeth with cylindrical shanks and a working rock cutting head in the form of ridges converging on a rounded apex, characterized in that the pyramidal working head in sections below the rounded apex has the form of a trapezoid with rounded corners, and the radii of rounding of the apex and ribs are connected by the following ratio with the diameter of the cylindrical part of the tooth and the number of faces of the pyramid:

,
where r ₁ is the radius of rounding of the top of the working head of the tooth, mm;
r ₂ is the radius of rounding of the ribs of the working head of the tooth, mm;
d is the diameter of the cylindrical part of the tooth, mm;
n is the number of faces of the pyramidal working head of the tooth. 2. The drill bit according to claim 1, characterized in that the carbide teeth are located on the crowns in the cone body with the orientation of the large side of the base of the pyramid on the recession side and the small side on the incident side relative to the direction of rotation of the cone.

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