RU2264521C1 - Rotary cutting drill bit - Google Patents

Abstract

FIELD: mining industry, particularly for drilling blast holes in mines or open pits and for making technological holes.

SUBSTANCE: drill bit has body with ribs, axes secured in ribs by spline connections and eccentric bushes on which toothed disc cutters are installed. Outer surfaces of eccentric bushes are inclined at α angle to axis to provide α_v angles of cutters inclination to vertical plane and α_h angles of cutters inclination to vertical plane of hole bottom. Angles α_v and α_h may be changed in dependence of physical mechanical properties of rock to be drilled. Relation between above angles satisfies the following equation: α=α_v+α_h, wherein angle between side edges of toothed disc cutters α_c=2α. Cutters have longitudinal grooves with trapezoid cross-sections at bases thereof adapted for alternately receiving hard-alloy teeth and intermediate sections having the same trapezoid cross-section at bases thereof. Number of hard-alloy teeth N is determined in dependence of rigidity f of rock to be drilled as

, where D_c is diameter of toothed disc cutter and D_t is diameter of working hard-alloy tooth part.

EFFECT: increased operational efficiency and extended range of efficient usage thereof in solid rock having composite structure with different physical mechanical properties and in karst massifs.

4 cl, 6 dwg, 2 tbl

Description

The invention relates to the mining industry and can be used for drilling blast holes in quarries and mines, as well as for sinking technological wells.

Known drill bits with rotating cutters for coal mines, containing a housing, interchangeable rotating cutters and sliding bearings (Butkin V.D., Teleshov A.S., Bryukhov E.F. Drill bits with rotating cutters for cuts. M., Central Research Institute for Coal Mine, 1976, p. 8, fig. 1 and p. 11, fig. 2). The disadvantages of such bits: rotating cutters are fixed in the edges of the housing on sliding bearings in such a way that the axis of rotation is perpendicular to the diametrical plane of the bit, and when drilling complex structural rocks containing abrasive and strong inclusions (with a coefficient of strength f = 8-10), the armament of rotating cutters is premature fails due to chipping of carbide teeth due to increased moments of rotation and cutting forces acting on the cutters. In addition, rotating cutters are reinforced with the same number of carbide teeth for rocks of various strengths, which also leads to their premature wear. The noted drawbacks limit the use of these bits in complex structural rocks.

A drill bit is known, consisting of a body, in the grooves of which rock-cutting disks are located with the possibility of changing their inclination from 0 to 20 ° depending on the physicomechanical properties of the rock being destroyed (Chesnokov V.T., Butkin V.D., Gilev A.V. . and others. The method of secondary use of drill bits. Patent No. 2149974. Publ. 27.05.2000. B.I. No. 15).

The disadvantages of this bit include the lack of the ability to control the angle of inclination of rock-cutting disks during its operation. During the restoration of the drilling tool, rock cutting disks are installed in the grooves of the body with a fixed angle in the horizontal plane, without taking into account changes in the physicomechanical properties of rocks within the block or ledge. In the vertical plane, a change in the angle of the rock-cutting disks is impossible, which does not allow reducing the loads acting on the armament, especially under power regimes of drilling rocks with a complex structure. In addition, rock cutting disks have a rectangular cross section, which leads to their jamming during drilling in karst massifs with the presence of wet and viscous clay due to the inability to intensively clean the bit due to the small gap between the side faces of the rock cutting disks and the edges of the body.

Closest to the proposed technical solution is the drill bit adopted for the prototype, which contains a body with ribs fixed in the ribs by means of spline joints of the axle and eccentric bushings on which the gear-disk cones are installed (Gilev A.V., Butkin V.D. and others Cutting drill bit. Patent No. 2081989. Publish. 06/20/1997. B. I. No. 17).

The main disadvantage of the prototype is that it is impossible to change the angle of inclination of the gear-wheel cones and the number of carbide teeth installed on them depending on the change in the physicomechanical properties of drill bits, which reduces the bit durability and limits its scope in hard, complex structural and karst rocks arrays.

The main objectives of the invention are: improving the efficiency of the bit and expanding the field of rational use in strong, complex structural rocks with various physical and mechanical properties and karst massifs by optimizing its structural and kinematic parameters, drilling process modes, increasing the intensity of well cleaning from drill cuttings and increasing weapons durability.

где D_ш - диаметр зубчато-дисковой шарошки, D_з - диаметр рабочей части твердосплавного зуба; кроме того, при бурении горных пород с пневматической очисткой скважин от бурового шлама его конструктивные параметры отвечают условиюThe objectives are achieved in that in a drill bit of a cutting-rotary type, comprising a housing with ribs, axles and eccentric bushings mounted on the ribs with spline joints, on which gear-disk cones are mounted, the outer surfaces of the eccentric bushings are made at an angle of inclination α to the axis, providing arrangement on them of gear-disk cones at angles of inclination α _in to the vertical plane and α _g to the horizontal plane of the bottom of the well, with the possibility of their change depending on the physicomechanical properties of drill rocks, and the ratio of angles meets the condition α = α _in + α _g , while the angle between the side faces of the gear-disk cones α _b = 2α, and the gear-tooth cones have longitudinal grooves with a trapezoidal cross-section at the base, in which carbide teeth and intermediate sections having alternating trapezoidal sections of their bases are installed alternatingly, the number of carbide teeth N being determined depending on the strength of the drill rock f by the expression

_w where D - diameter toothed disk bit, D _s - diameter of the working part of the tooth carbide; in addition, when drilling rocks with pneumatic cleaning of wells from drill cuttings, its design parameters meet the condition

, где S_d - площадь поперечного сечения долота, перекрывающего площадь сечения скважины S_c; D_k - диаметр корпуса; D_c - диаметр скважины; k=1,2-1,3 - коэффициент, учитывающий наличие в корпусе продувочных окон; h и β - соответственно ширина и число зубчато-дисковых шарошек, установленных на долоте, причем для удаления налипающей породы при бурении скважин в закарстованных массивах в корпусе выполнены продувочные каналы, обеспечивающие подачу высокоскоростных струй сжатого воздуха непосредственно в рабочую зону зубчато-дисковых шарошек.

where S _d is the cross-sectional area of the bit, overlapping the cross-sectional area of the well S _c ; D _k is the diameter of the housing; D _c is the diameter of the well; k = 1.2-1.3 - coefficient taking into account the presence of purge windows in the housing; h and β are, respectively, the width and number of gear-disk cones mounted on the bit, and to remove sticking rock when drilling wells in karst arrays, purge channels are made in the casing to supply high-speed jets of compressed air directly to the working area of the gear-cones.

The causal relationship of the essential features characterizing the invention with the achieved technical and technological results is as follows.

Stable operation of gear-disk cones, i.e. work without jamming is ensured under the following conditions: M _W > M _m , where M _W is the moment that rotates the gear-disk cone around its axis; M _m - total moment of friction, counteracting the moment M _W The installation of gear-disk cones on eccentric bushings with an angle of inclination in the vertical plane optimizes the design and kinematic parameters of the bit and, as a hallmark of the proposed device, reduces the cutting force, and therefore the moment M _m . Since M _m increases with increasing strength of drill rocks, this increase is offset by its decrease due to the installation of gear-disk cones with an angle of inclination in the vertical plane of the bottom of the well. At the same time, the drilling process modes are optimized: a stable operation mode of gear-disk cones is maintained, it becomes possible to increase the axial force on the bit and destroy the rock in power mode, which increases the depth of penetration of gear-disc cones into the rock and increases the speed of well drilling.

Optimization of structural and kinematic parameters, which consists in installing gear-disk cones with an angle of inclination in the horizontal plane of the bottom of the well, as a hallmark of the claimed device allows you to change the cutting angle of carbide teeth when drilling rocks of different strengths and, thereby, optimize the drilling process, as well as reduce the moment of rotation of the gear-disk cones around the axis of the bit; this reduces the energy intensity of the process of destruction of the rock. The inclination angles depend on the strength of drill rock, and with increasing strength, the vertical angle of inclination α _in increases and the horizontal angle α _g decreases, while their sum remains equal to the angle of inclination of the outer surfaces of the eccentric bushings to the axes α = α _in + α _g , which is due to structural and kinematic parameters of the claimed bit.

With a change in the angles of inclination α _in and α _g , depending on the strength of the drill, hard-alloy teeth with corresponding sharpening angles of the working parts are installed on the gear-wheel cones. For weak rocks, carbide teeth with sharper sharpening angles are used than when drilling hard rocks. With an increase in the strength of drill rocks, sharpening angles increase. Thus, the distinguishing feature of the inventive bit, which consists in the installation of carbide teeth with sharpening angles of their working parts, corresponding to the strength of drill bits and the angles of inclination of gear-disk cones to the bottom of the well, increases the service life of the armament of the drilling tool.

To effectively clean and prevent jamming during drilling of wells in karst massifs, the tooth-disk cones have a conical cross-sectional shape, and the angle between their side faces is α _b = 2α as a hallmark. This ratio is explained by the fact that for α _b > 2α, the tooth-disk cones are jammed in the grooves of the body, and for α _b <2α, intensive wear of the side faces and protective washers occurs due to high contact loads during drilling.

Longitudinal grooves available on the gear-roller cones, as a distinguishing feature of the claimed device, allow, firstly, to carry out mechanical fastening of carbide teeth, which eliminates the problem of their extraction after working out the bits of their service life, and secondly, to use carbide teeth with different geometries and different sizes of working surfaces when drilling rocks with a wide range of changes in physical and mechanical properties, thirdly, to place a different number of carbide teeth, depending on Drill Fortresses.

Optimization of the design parameters of the bit (body diameter, width and number of gear-disk cones) as a hallmark of the inventive bit provides effective removal of drill cuttings from the well. This is achieved provided that the ratio of the cross-sectional area of the bit and the section of the well is equal to S _d / S _with = 0.5-0.65. When the ratio S _d / S _c <0.5, the flow rate of compressed air becomes less critical, and the process of cleaning the well from drill cuttings is ineffective. When S _d > 0.65, the tightness of the flow of drill cuttings in the bottomhole zone increases, which can lead to a significant deterioration in bottom hole cleaning, especially when drilling in wet and karst massifs containing clay inclusions.

In order to increase the efficiency of cleaning wells in these rocks, purge channels are provided that provide high-speed jets of compressed air directly to the working area of the gear-disk cones. This distinctive feature allows you to intensify the process of cleaning the well and, thereby, increase the durability of the bit.

Thus, a set of new significant solutions expands the technical and technological capabilities of the bit and the drilling process in strong, complex structural rocks and karst massifs by optimizing its structural and kinematic parameters that determine the rational modes of the drilling process, the installation angles of gear-disk cones in the housing relative to the bottom hole , improving their equipping with carbide teeth, the number of which is determined depending on the strength of the drill, and also due to increase the intensity of well cleaning from drill cuttings and increase the durability of weapons. These new solutions ultimately achieve the objectives.

The invention is illustrated by graphic materials, which depict:

figure 1 - the location of the gear-disk cones in the housing at an angle in the horizontal plane of the bottom of the well;

figure 2 - the location of the gear-disk cone in the housing at an angle of inclination in the vertical plane of the bottom of the well (section aa of figure 1);

figure 3 - the location of the elements of weapons on the gear-wheel cone;

figure 4 is a section bB of figure 3;

figure 5 - the location of the eccentric sleeve on the axis when installing the gear-wheel cone at an angle in the vertical plane of the bottom of the well (section BB of figure 2);

in Fig.6 - the location of the eccentric sleeve on the axis when installing the gear-disk cone at an angle of inclination in the horizontal plane of the bottom of the well (section BB of Fig.2).

The drill bit of the cutting-rotary type contains (Figs. 1 and 2) a housing 1 with ribs 2, in which gear teeth are located 3, equipped with carbide teeth 4 and mounted on eccentric bushings 5, mounted on axis 6. Between the side faces of the gear protective washers 7 are located on the axles 6 of the disk cones 3 and ribs 2. The central purge hole 8 and the purge channels 9 are made in the housing 1. The tooth-disk cones 3 have longitudinal grooves 10 (FIGS. 3 and 4) with a trapezoidal cross-section at the base 11 in which the hard drive is installed smooth teeth 4 and intermediate sections 12. The longitudinal groove 10 is equipped with a loading window 13 overlapped by the wedge 14. The eccentric bushings 5 are mounted on the axles 6 by means of splined joints 15 (FIG. 5) and have external surfaces 16 made with an angle of inclination to these axes (FIG. .6).

The method of using the proposed bit is as follows. The inclination angles of the gear-wheel cones 3 in the vertical plane α _in (FIG. 2) and the horizontal plane α _g (FIG. 1) of the bottom hole are selected depending on the strength coefficient of drill bits f, which determines the depth of penetration of the bit h into the rock in one revolution and, consequently, the penetration rate, depending on the drilling regimes - axial force, rotation speed and conditions for cleaning the well from drill cuttings. Given the adopted drilling modes, the rational values of the angles of inclination of gear-disk cones to the bottom of the well are selected according to table 1.

Table 1
Rational values of the angle of inclination of gear-disk cones f 10-8 8-6 6-4 4-2 h, mm / rev 5-10 10-15 15-20 20-25 α _g , deg 0-2 6-8 8-10 10-12 α _in deg 10-12 4-6 2-4 0-2 α, degree 10-14 10-14 10-14 10-14 Eccentric Bushing Position Number 1 2 3 4

Before drilling a well, the required angles of inclination of the gear-disk cones 3 are set using spline joints 15 of the eccentric bushings 5, giving them an appropriate position by moving the axles 6 on the slots. for example, corresponds _to α = α = (10-14) for a drill bit diameter of 244.5 mm (DZDSH-244.5) to position 1 of the eccentric bushing 5 (5) °, and when _r = (0-2) ° . In this position, the gear-wheel cones 3 have a maximum angle of inclination in the vertical plane of the bottom of the well (figure 2). Position 4 of the eccentric sleeve 5 corresponds to α _g = α = (10-14) °, at α = (0-2) ° (Fig.6). In this position, the gear-wheel cones 3 have a maximum angle of inclination in the horizontal plane of the bottom of the well (figure 1). Before assembling the bit into the longitudinal grooves 10 of the gear-wheel cones 3, carbide teeth 4 and intermediate sections 12 are alternated through the loading window 13 (Fig. 3). The number of carbide teeth 4 is selected depending on the diameter of their working part and the diameter of the bit, which determines the diameter of the gear-wheel cones 3, as well as on the strength of the drill. So, for example, for a bit with a diameter of D _d = 244.5 mm (DZDSH-244.5) with a diameter of gear-wheel cones D _w = 110 mm, the optimal number N of hard-alloy teeth 4, the diameter of the working part of which D _s = 10 mm, has the following values (table 2).

table 2
The optimal number of carbide teeth for the bit DZDSH-244.5 f 10-8 8-6 6-4 4-2 N 16 thirteen eleven 10

After installing the full set of carbide teeth 4 and intermediate sections 12 in the longitudinal grooves 10 of the gear-wheel cones 3, the loading window 13 is closed with a wedge 14 (Fig. 4), which is fixed to the case of the gear-wheel cones 3 by soldering. Dismantling of weapons elements (carbide teeth 4 and intermediate sections 12) of gear-roller cones 3 is carried out in the reverse order. In the process, carbide teeth 4 and intermediate sections 12 due to trapezoidal cross-sectional shapes of their bases are kept from falling out of longitudinal grooves 10, the base 11 of which are made with a similar trapezoidal cross-sectional shape (figure 4). For a specific number of carbide teeth 4, there is a separate set of intermediate sections 12 with their sizes. In this case, carbide teeth 4 can be made with different sizes, depending on the physicomechanical properties of drill rocks, including different sharpening angles δ. For example, for soft rocks (f = 4-2), the angle of sharpening δ ₁ = (35-40) °, and for hard rocks (f = 8-10) the angle of sharpening δ ₂ = (85-90) ° (Fig. 4 )

When drilling wells in karst massifs with the presence of wet clays, a nozzle (not shown) with a smaller cross section of the blowing hole is inserted into the central purge hole 8 (Fig. 1). In this case, the amount of compressed air is distributed along the purge channels 9 (Figs. 1 and 2) with a significant increase in its speed, which ensures effective cleaning of the working surface of the gear-disk cones 3, protective washers 7, grooves between the ribs 2 of the housing 1 and the bottom of the well. Protective washers 7 are installed on the axles 6 by means of splined joints 15. They do not rotate and protect the inner surfaces of the ribs 2 of the housing 1 from premature wear.

The mechanical fastening of carbide teeth 4 on gear-roller cones 3 allows you to quickly and without additional costs to carry out their extraction. Worn carbide teeth 4 are sent for recycling, and suitable for further use - for reuse. This saves the cost of expensive cermet hard alloys.

It should be noted that for each carbide tooth 4 when the rotation of the gear-wheel cone 3 around its axis, the signs and values of the angle of inclination α _in and α _g change. So, when moving in a vertical plane for each carbide tooth 4, the angle of inclination α _in changes from + α _in (carbide tooth 4 is in the lower position) to -α _in (carbide tooth 4 is in the upper position) (figure 2). When moving in the horizontal plane for each carbide tooth 4, the angle of inclination α _g changes from + α _g (in the peripheral part of the bottom of the well) to -α _g (in the central part of the bottom of the well) (Fig. 1). Thus, the carbide tooth 4, making a complex trajectory of movement, destroys the rock in the bottom of the well with a constantly changing cutting angle. In addition, the tilt angles α _in and α _g can be not only positive when the gear-wheel cones 3 have a slope in the direction of their rotation around the vertical axis of the bit, but also negative when the gear-wheel cones 3 have a tilt in the opposite direction along relative to the direction of their rotation around the vertical axis of the bit. In this case, the eccentric bushings 5 on the axles 6 are set in such a way that the centers of the circumferences of their side surfaces are located in the reverse sequence indicated in FIGS. 5 and 6, namely: t. 0 ₂ in the upper part (negative vertical angle α _in , position 1), etc. 0 ₂ - on the left (negative horizontal angle α _g , position 4). Thus, the values of the angles of inclination α _in and α _g gear-roller cones 3 to the bottom of the well can be doubled. The specified kinematic parameters of the inventive bit also expand its technical and technological capabilities.

Thus, the structural and kinematic parameters of the inventive drill bit provide an extension of the technical and technological fields of its application and allow for efficient drilling of wells in strong, complex structural rocks with various physical and mechanical properties and in karst massifs.

Claims (4)

1. A drill bit of a cutting-rotary type, comprising a housing with ribs, fixed in the ribs by means of spline joints of the axis and eccentric bushings on which gear and disc cutters are mounted, characterized in that the outer surfaces of the eccentric bushings are made with an angle of inclination α to the axis, providing the arrangement on them of gear-disk cones at angles of inclination α _in to the vertical plane and α _{g of the} horizontal plane of the bottom of the well, with the possibility of changing them depending on the physicomechanical properties of the drill rocks, and the ratio of the angles meets the condition α = α _in + α _g , while the angle between the side faces of the toothed disk cones α _in = 2α. 2. The bit according to claim 1, characterized in that the gear-wheel cones have longitudinal grooves with a trapezoidal section at the base, in which carbide teeth are mounted alternately, and intermediate sections having a similar trapezoidal section of their bases, the number of carbide teeth N is determined depending on the strength of drill rocks by the expression

where D _W - the diameter of the gear-wheel cone; D _s - the diameter of the working part of the carbide tooth; f is the rock strength coefficient. 3. The bit according to claim 1, characterized in that when drilling rocks with pneumatic cleaning of wells from drill cuttings, its design parameters meet the condition

where S _d is the cross-sectional area of the bit, overlapping the cross-sectional area of the well S _c , D _k is the diameter of the housing, D _c is the diameter of the well, k = 1.2-1.3 - coefficient taking into account the presence of purge windows in the housing, h and β are, respectively, the width and number of gear-disk cones mounted on the bit. 4. The bit according to claim 1, characterized in that for removing sticking rock during drilling of wells in karst massifs, purge channels are made in the casing, providing high-speed jets of compressed air directly to the working area of the gear-disk cones.

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