CN114151013A - Large-diameter hole expanding drill bit while drilling in underground coal mine - Google Patents
Large-diameter hole expanding drill bit while drilling in underground coal mine Download PDFInfo
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- CN114151013A CN114151013A CN202111376456.4A CN202111376456A CN114151013A CN 114151013 A CN114151013 A CN 114151013A CN 202111376456 A CN202111376456 A CN 202111376456A CN 114151013 A CN114151013 A CN 114151013A
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- reaming
- pilot
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/26—Drill bits with leading portion, i.e. drill bits with a pilot cutter; Drill bits for enlarging the borehole, e.g. reamers
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B10/00—Drill bits
- E21B10/60—Drill bits characterised by conduits or nozzles for drilling fluids
- E21B10/602—Drill bits characterised by conduits or nozzles for drilling fluids the bit being a rotary drag type bit with blades
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
Abstract
The invention discloses a large-diameter while-drilling reaming bit for an underground coal mine, which comprises a pilot bit and a reaming bit which are coaxially connected; the pilot bit comprises a pilot bit body, a plurality of pilot blades arranged around the circumference of the pilot bit body, cutting teeth arranged on the cloth tooth surfaces of the pilot blades and gauge alloy on the gauge surfaces of the pilot blades, wherein a first chip discharge groove is formed between every two adjacent pilot blades, and a first water hole is formed in each first chip discharge groove; the reaming bit comprises a reaming bit body, a plurality of reaming blades arranged around the circumference of the reaming bit body, supporting rib plates arranged between the adjacent reaming blades, cutting teeth arranged on the cloth tooth surfaces of the reaming blades and gauge alloy on the gauge surfaces of the reaming blades, wherein second chip grooves are formed between the adjacent reaming blades, and second water holes are formed in the second chip grooves; the invention is a two-stage cutting structure consisting of a pilot bit and a reaming bit, can reasonably distribute drilling pressure, realizes a drilling mode of drilling and reaming simultaneously, and improves the hole forming efficiency of the drilling of a large-diameter connecting roadway.
Description
Technical Field
The invention belongs to the technical field of coal mine drilling, and particularly relates to a large-diameter underground coal mine reaming-while-drilling drill bit.
Background
With the increase of coal mining depth, underground construction conditions are increasingly complex, and the requirements of underground roadway construction cannot be met by conventional roadway construction technologies. The large-diameter drilling technology opens up a new construction way for part of tunnel construction in coal mine production, can replace coal bunker chute holes, communication tunnels and the like, and has outstanding advantages in the aspects of tunnel ventilation, emergency rescue, underground pipeline laying and the like.
The larger the diameter of the drilled hole is, the more beneficial to the development of operations such as pipeline laying, roadway ventilation and the like, and for large-diameter drilled holes, the hole forming process of 'pilot hole construction and hierarchical hole expansion' is usually adopted at present, so that the defects of long auxiliary operation time and low hole expansion and hole forming efficiency exist.
The patent document with the publication number of CN209724230U proposes a reaming-while-drilling drill bit, in which a guide part and a reaming part of the drill bit adopt non-coaxial eccentric structures, after a hole is drilled to a designed well depth by an open hole, the drill bit is put in and penetrates through the open hole section to drill by reaming-while-drilling, the requirement of large-diameter connection roadway pore-forming of a coal full-hole section cannot be met, and the problem of difficulty in coal dust slag removal exists. The patent document of publication No. CN 104763348A proposes a drilling and reaming integrated drilling tool with embedded bionic nozzles, which is provided for grouting construction and comprises a pilot bit, a multi-stage reamer, an impactor and other components, the final hole forming operation can be completed only by configuring the multi-stage reamer, the annular space between the reaming bits at all stages is small, and the slag removal capacity of pulverized coal is weak.
Disclosure of Invention
Aiming at the technical problems, the invention provides the large-diameter reaming-while-drilling drill bit for the coal mine, which improves the hole forming efficiency of large-diameter drilling by a mode of drilling and reaming simultaneously, prolongs the service life of the drill bit and reduces the construction cost.
The invention is realized by adopting the following technical scheme:
a large-diameter hole expanding drill bit while drilling in a coal mine comprises a pilot drill bit and a hole expanding drill bit which are coaxially connected; the pilot bit comprises a pilot bit body, a plurality of pilot blades arranged around the circumference of the pilot bit body, cutting teeth arranged on the cloth tooth surfaces of the pilot blades and gauge alloy on the gauge surfaces of the pilot blades, wherein a first chip groove is formed between every two adjacent pilot blades, and a first water hole is formed in the first chip groove;
the reaming bit comprises a reaming bit body, a plurality of reaming blades arranged around the circumference of the reaming bit body, supporting rib plates arranged between the adjacent reaming blades, cutting teeth arranged on the cloth tooth surfaces of the reaming blades and gauge alloy on the gauge surfaces of the reaming blades, wherein second chip grooves are formed between the adjacent reaming blades, and second water holes are formed in the second chip grooves;
the reaming bit body is coaxially connected with the pilot bit body; the diameter of the profile formed by one rotation of the outermost tooth of the reaming wing is larger than that of the profile formed by one rotation of the outermost tooth of the pilot wing.
Preferably, the diameter D of the profile formed by one rotation of the outermost tooth of the pilot blade1Diameter D of profile formed by one rotation of outermost tooth of reaming blade2The ratio h of (a) satisfies the formula (15),
h＝-6.78777624401209k3+8.0441811186145k2-3.73768694982173k+1.29372621712326 (15)
in the equation (15), k is the bit pressure distribution ratio.
More preferably, h is 0.62 to 0.68.
Preferably, the diameter d of the first port1Diameter d of the second port2Has a ratio of
Wherein n is the number of the first water holes, and m is the number of the second water holes。
Preferably, the reaming blades are removably attached to the reaming bit body.
Specifically, a first positioning groove and a second positioning groove are formed in the reaming bit body, a third positioning groove is formed in the reaming blade, and a bolt hole is formed in the bottom of the third positioning groove; the reaming wing is inserted into the first positioning groove, one end of the supporting rib plate is inserted into the second positioning groove, two sides of the supporting rib plate are respectively provided with a bulge, and the bulges are respectively inserted into the third positioning grooves of two adjacent reaming wings and are fixed through bolts.
Preferably, the plurality of supporting ribs are arranged in a spiral line around the reaming bit body.
Preferably, the reaming blade and the supporting rib plate are provided with holes.
Preferably, the inner cone area of the cloth tooth surface of the pilot cutter wing is provided with cylindrical PDC cutting teeth, the nose area of the cloth tooth surface of the pilot cutter wing is provided with axe-type ridged PDC cutting teeth, and the outer cone area of the cloth tooth surface of the pilot cutter wing is provided with triangular ridged PDC cutting teeth.
Preferably, the contour line of the cloth tooth surface of the pilot cutter wing is formed by sequentially and tangentially connecting a first straight line segment, a first arc segment and a second arc segment, and the second arc segment is connected with the gauge surface of the pilot cutter wing; the included angle between the first straight line segment and the vertical direction is 77.5-87.5 degrees, and the distance between the highest point of the cloth tooth surface contour line of the pilot cutter wing and the central line of the pilot drill bit is 0.3D1～0.34D1，D1The diameter of the profile formed by one rotation of the outermost tooth of the pilot blade.
Preferably, the contour line of the tooth surface of the reaming blade cloth is formed by connecting a second straight section and a third circular arc section in a tangent mode, and the third circular arc section is connected with the gauge surface of the reaming blade in a tangent mode; and axe-type ridged PDC cutting teeth and triangular ridged PDC cutting teeth are arranged on the third arc section.
Compared with the prior art, the invention has the beneficial effects that:
(1) the invention adopts a two-stage cutting structure consisting of a pilot bit and a reaming bit, the structural design can reasonably distribute the bit pressure, realize the drilling mode of drilling and reaming simultaneously, and improve the hole forming efficiency of the drilling of the large-diameter connecting roadway.
(2) The reaming bit adopts an assembly type structure, and the reaming blades are fixed on the reaming bit body through the supporting rib plates, so that the number of the reaming blades can be flexibly increased or decreased according to the hardness of rocks, the drilling efficiency is ensured, and the service life of the bit is prolonged; on the other hand, the reaming blades can be replaced at any time according to the abrasion condition of the cutting teeth on the reaming blades, so that the manufacturing period of the drill bit is favorably shortened, and the aggressiveness of the drill bit is kept all the time.
Other advantages of the present invention are described in detail in the detailed description of the invention.
Drawings
Fig. 1 is a schematic view of the overall structure of a reamer bit while drilling according to an embodiment of the present invention.
FIG. 2 is a schematic representation of a structure of a reamer bit body according to an embodiment of the present invention.
Fig. 3 is a schematic structural view of a reamer blade according to an embodiment of the present invention.
Fig. 4 is a schematic view of a reamer blade tooth according to an embodiment of the present invention.
Fig. 5 is a schematic view of a tooth surface structure of a reamer blade according to an embodiment of the present invention.
Fig. 6 is a schematic view of arrangement of cutting teeth on the leading-eye blade cloth tooth surface according to an embodiment of the present invention.
Fig. 7 is a schematic view of a tooth surface structure of a pilot blade according to an embodiment of the present invention.
Fig. 8 is a schematic view of a tooth surface contour of a reamer blade according to an embodiment of the present invention.
Fig. 9 is a schematic diagram of a tooth surface contour line of a leading-eye wing according to an embodiment of the present invention.
FIG. 10 is the diameter D of the profile formed by one revolution of the outermost tooth of the pilot blade1Diameter D of profile formed by one rotation of outermost tooth of reaming blade2Finite element simulation stress cloud pictures calculated by ratio, wherein (a) is a finite element model picture, and (b) is a stress cloud picture.
FIG. 11 is a finite element calculated diameter D1And diameter D2Is plotted against the bit pressure distribution ratio k.
FIG. 12 is a finite element calculated diameter D1And diameter D2The specific value h and the rock breaking specific work curve of the reaming bit while drilling.
The various reference numbers in the figures illustrate:
1-pilot bit, 2-reaming bit, 3-cutting tooth, 4-gauge alloy, 5-reverse alloy, 6-bolt and 7-rock;
11-pilot bit body, 12-pilot wing, 13-first chip groove, 14-first water hole;
121-the tooth surface of the cloth of the pilot hole blade and 122-the gauge surface of the pilot hole blade;
1211-a first straight line segment, 1212-a first circular arc segment, 1213-a second circular arc segment;
21-reaming bit body, 22-reaming wing, 23-supporting rib plate, 24-second chip groove, 25-second water hole and 26-hole;
211-a first positioning groove, 212-a second positioning groove;
221-reaming blade cloth tooth surface, 222-reaming blade gauge surface, 223-inclined surface, 224-third positioning groove and 225-bolt hole;
2211-second straight line segment, 2212-third circular arc segment;
31-plane cylindrical PDC cutting teeth, 32-axe type ridged PDC cutting teeth and 33-triangular ridged PDC cutting teeth.
Detailed Description
The following description of the present invention is provided for the purpose of illustration, and unless otherwise explicitly stated or limited, the terms "disposed" and "connected" are to be construed broadly and may include, for example, a fixed connection or a detachable connection or an integral connection; either a direct connection or an indirect connection, and the like. The specific meaning of the above terms in the present technical solution can be understood by those of ordinary skill in the art according to specific situations.
In the present invention, unless otherwise specified, the terms of orientation such as "upper, lower, bottom, top" are generally defined with reference to the drawing plane of the corresponding drawing, "inner and outer" are defined with reference to the outline of the corresponding drawing, and "front and rear" are defined with reference to the gas flow direction.
The present invention is not limited to the following embodiments, and various specific technical features described in the following embodiments may be combined in any suitable manner without contradiction, as long as they do not depart from the idea of the present invention, and should be considered as the disclosure of the present invention.
The specific embodiment of the invention discloses a large-diameter hole-expanding-while-drilling drill bit for underground coal mines, and as shown in fig. 1, the large-diameter hole-expanding-while-drilling drill bit comprises a pilot drill bit 1 and a reaming drill bit 2 which are coaxially connected.
The pilot bit 1 comprises a pilot bit body 11, a plurality of pilot blades 12 arranged around the circumference of the pilot bit body 11, cutting teeth 3 arranged on a pilot blade cloth tooth surface 121, and a gauge alloy 4 on a pilot blade gauge surface 122. The pilot bit body 11 is a cylinder with a through hole at the center, a first chip groove 13 is formed between adjacent pilot blades 12, a first water hole 14 is processed in the first chip groove 13, and the first water hole 14 is communicated with the center hole of the pilot bit body 11.
The pilot cutter blades 12 of the embodiment are 3-4 in number, and the cutting teeth 3 comprise plane cylindrical PDC cutting teeth 31, axe-type ridged PDC cutting teeth 32 and triangular ridge PDC cutting teeth 33. The diamond layer of the axe-type ridged PDC cutting tooth 32 is of a double-deflection-wedge-surface structure with ridges, the axe-type ridged PDC cutting tooth 32 cuts into rock with the lower end of an axe blade, and high stress concentration is formed in the rock, so that the instantaneous mechanical drilling speed of a drill bit is improved; the center of the diamond layer of the triangular ridge PDC cutting tooth 33 is of a triangular plane crown structure, three eccentric surfaces are uniformly distributed around the circumference of the crown, three ridge lines of the crown are respectively connected with the three eccentric surfaces, only one shorter ridge line is used as a cutting edge to cut into rock when the triangular ridge PDC cutting tooth 33 drills, and the other two ridge lines are not meshed with the rock, so that the control of a tool face is easier to strengthen when the cutting tooth drills. The gauge alloy 4 is strip-shaped, and 2-3 rows of gauge alloys 4 are welded on each pilot hole blade gauge surface 122.
The reamer bit 2 includes a reamer bit body 21, a plurality of reamer blades 22 circumferentially disposed about the reamer bit body 21, support ribs 23 disposed between adjacent reamer blades 22, cutting teeth 3 disposed on the reamer blade cloth tooth face 221, and gage alloy 4 on the reamer blade gage face 222. The reaming bit body 21 is a cylinder with a central processing through hole, a second chip groove 24 is formed between the adjacent reaming blades 22, a second water hole 25 is arranged in the second chip groove 24, and the second water hole 25 is communicated with the central through hole of the reaming bit body 21.
The number of the reaming blades 22 in this embodiment is 6-10, the shape of the reaming blades 22 is a plate structure, as shown in fig. 3, one side of the plate is a flat side and is used for connecting the reaming bit body 21, and the other sides of the plate are used for arranging the cutting teeth 3, the gauge-protecting alloy 4, the reverse alloy 5 and the like.
Wherein the diameter D of the profile formed by one rotation of the outermost teeth of the reaming blades 222Is larger than the diameter D of the outline formed by one rotation of the outermost tooth of the pilot hole blade1。
The cutting teeth 3 on the tooth surface 221 of the reaming blade wing also adopt the combined arrangement form of a plane cylindrical PDC cutting tooth 31, an axe-type ridge-shaped PDC cutting tooth 32 and a triangular ridge-shaped PDC cutting tooth 33. And the outer diameter of the reaming bit body 21 is smaller than that of the pilot bit 1, so that the arrangement of the cutting teeth 3 on the pilot bit 1 and the reaming bit 2 can completely cover the hole bottom. The cutting teeth 3 are arranged in a layered and staggered mode along the tooth surface 121 of the pilot wing cloth and the tooth surface 221 of the reaming wing cloth, medium-density tooth distribution is adopted for the cutting teeth 3, and the center distance between every two adjacent cutting teeth 3 is 17.3-17.8 mm.
The pilot bit 1 of the embodiment is generally a crown knot with shallow inner cone and short parabolic surfaceThe structure specifically is: as shown in fig. 9, the contour line of the leading-eye blade cloth tooth surface 121 is formed by sequentially and tangentially connecting a first straight line 1211, a first circular arc segment 1212, and a second circular arc segment 1213, and the second circular arc segment 1213 is connected with the contour line of the leading-eye blade gage surface 122. Wherein the included angle between the first straight line 1211 and the vertical direction is 77.5-87.5 degrees, and the distance between the highest point of the contour line of the cloth tooth surface 121 of the pilot cutter wing and the central line of the pilot drill bit 1 is 0.3D1～0.34D1，D1The diameter of the profile formed for one revolution of the outermost tooth of the pilot blade 12 in the pilot bit.
Preferably, in this embodiment, the shapes of the first straight line segment 1211, the first circular arc segment 1212, and the second circular arc segment 1213 respectively satisfy the following relations:
a coordinate system is established by taking a central conical point of the pilot bit 1 as an origin O, the axial direction of the pilot bit body 11 as a y-axis and the radial direction of the pilot bit body 11 as an x-axis, as shown in FIG. 8. The first straight line 1211 satisfies the following relation:
y＝x·cotα (1)
in the formula: x is the abscissa of any point of the first straight line 1211, y is the ordinate of any point of the first straight line 1211, and α is the inner cone angle.
For the first arc segment 1212 of the contour line of the tooth surface of the cloth of the pilot hole blade, the circle center M (x) isM,yM) Can be expressed as:
thus, the first arc segment 1212 satisfies the following relationship:
in the formula: x is the abscissa of any point of the first arc segment 1212, y is the ordinate of any point of the first arc segment 1212, and R1Is the radius, x, of the first arc segment 1212AIs the abscissa, y, of the point of intersection of the first arc segment 1212 and the first straight segment 1211AIs the ordinate of the point where the first circular arc segment 1212 intersects the first straight line segment 1211.
For the second arc section 1213 of the contour line of the tooth surface of the pilot wing, the circle center M (x) isN,yN) Can be expressed as:
thus, the second arc segment 1213 satisfies the following relationship:
in the formula: x is the abscissa of any point of the second arc segment 1213, y is the ordinate of any point of the second arc segment 1213, R2Is the radius of the second arc segment 1213, xBIs the abscissa, y, of the point of tangency of the second arc segment 1213 with the first arc segment 1212BIs the ordinate of the point of tangency of the second arc segment 1213 with the first arc segment 1212, D1The diameter of the profile formed for one revolution of the outermost tooth of the pilot blade 12, epsilon ═ D1-D′1，D′1The diameter of the profile formed for one rotation of the outermost peripheral surface of the pilot blade 12. The diameter D of the profile formed by one rotation of the outermost tooth of the common pilot blade 121Diameter D 'of contour formed on outermost peripheral surface of pilot blade'1The size of the lens is 1-2 mm, i.e. the epsilon is 1-2 mm.
In addition, the contour line of the leading-eye blade gage surface 122 satisfies the following relational expression:
x＝(D1-ε)/2 (9)
in the formula: and x is the abscissa of any point of the contour line of the pilot blade gage surface 122. In the present embodiment, the first and second electrodes are,
the arrangement form of the cutting teeth 3 on the leading-eye wing cloth tooth surface 121 of the embodiment is as follows: as shown in fig. 6, a cylindrical PDC cutter 31 is disposed in an inner cone region of the pilot blade cloth tooth surface 121, an axe-type ridged PDC cutter 32 is disposed in a nose region of the pilot blade cloth tooth surface 121 to improve the capability of the cutters to invade into rock, and a triangular ridged PDC cutter 33 is disposed in an outer cone region of the pilot blade cloth tooth surface 121 to improve the controllability of the tool surface of the drill bit.
The contour line of the reamer blade cloth tooth surface 221 of the present embodiment is formed by tangentially connecting the second straight line segment 2211 and the third circular arc segment 2212, and the third circular arc segment 2212 is tangentially connected to the reamer blade gage surface 222, as shown in fig. 8.
Preferably, the shapes of the second straight line segment 2211 and the third circular arc segment 2212 respectively satisfy the following relations:
similarly, a coordinate system is established by taking the central conical point of the pilot bit 1 as the origin O, the axial direction of the pilot bit body 11 as the y-axis, and the radial direction of the pilot bit body 11 as the x-axis, as shown in fig. 7.
The second straight line segment 2211 satisfies the following relation:
y＝yE (10)
in the formula: y is the ordinate of any point in the second straight line segment 2211, yEThe distance from the starting point of the reamer blade 22 to the origin O.
The third arc segment 2212 satisfies the following relation:
[x+R3-(D2-γ)/2]2+(y-yE-R3)2＝R3 2 (11)
in the formula: x is the abscissa of any point of the third arc segment 2212, y is the ordinate of any point of the third arc segment 2212, and R3Is the radius of the third arc segment 2212, D2The diameter of the profile formed for one revolution of the outermost tooth of reamer blade 22. Gamma ═ D2-D′2，D′2The diameter of the profile formed for one rotation of the outermost peripheral surface of reamer blade 22. In general D2Than D'2The size of the gamma-1-2 mm is 1-2 mm.
In addition, the contour line of the reamer blade gage surface 222 satisfies the following relational expression:
x＝(D2-γ)/2 (12)
in the formula: x is the abscissa of any point of the contour of the reamer blade gage surface 222.
The arrangement of the cutting teeth 3 on the reamer blade cloth tooth surface 221 of the present embodiment is: cylindrical PDC cutting teeth 31 are respectively arranged at the partial position of the second straight line segment 2211 and the partial position of the reaming blade gauge surface 222 close to the third circular arc segment 2212, the axe-type ridge-shaped PDC cutting teeth 32 and the triangular ridge-shaped PDC cutting teeth 33 are arranged on the third circular arc segment 2212, wherein the axe-type ridge-shaped PDC cutting teeth 32 are arranged at 0.6D2～0.8D2Within the zone.
The reaming bit body 21 and the pilot bit body 11 are coaxially connected, specifically, the threaded connection is adopted, so that the pilot bit 1 or the reaming bit 2 can be flexibly replaced according to the abrasion condition of the drill bit in field use, and the cost of the drill bit is saved.
As a preferred scheme of the embodiment, the reaming blades 22 are detachably connected to the reaming bit body 21, which is beneficial to flexibly increasing or decreasing the number of the reaming blades 22 according to the hardness of the rock, thereby ensuring the drilling efficiency and prolonging the service life of the drill bit; on the other hand, the reaming blades 22 can be replaced at any time according to the abrasion condition of the cutting teeth 3 on the reaming blades 22, which is beneficial to shortening the manufacturing period of the drill bit and keeping the aggressiveness of the drill bit all the time. The detachable connection is realized through the following structure:
as shown in fig. 2, a first positioning groove 211 and a second positioning groove 212 are provided on the reaming bit body 21, the first positioning groove 211 and the second positioning groove 212 are grooves which are not penetrated through along the thickness of the reaming bit body, the first positioning groove 211 is vertically arranged, the second positioning groove 212 is horizontally arranged, the second positioning groove 212 is arranged between two adjacent first positioning grooves 211, a third positioning groove 224 is provided on the reaming blade 22, the third positioning groove 224 is also a groove which is not penetrated through along the thickness of the reaming blade 22, and a bolt hole 225 is provided at the bottom of the third positioning groove 224. The reaming blades 22 are inserted into the first positioning grooves 211, one end of the supporting rib plate 23 is inserted into the second positioning groove 212, two sides of the supporting rib plate 23 are respectively provided with a bulge, the bulges are respectively inserted into the third positioning grooves 224 of two adjacent reaming blades 22 and are fixed through bolts 6.
As a preferable scheme of this embodiment, the plurality of supporting ribs 23 are arranged in a spiral line around the reaming bit body 21, that is, adjacent supporting ribs 23 are connected to different positions of the reaming blades 22, as shown in fig. 1, and play a role in assisting in stirring powder and removing chips while being connected to the reaming blades 22. Due to the size limitations of the reamer blade 22, the six support ribs 23 of the present embodiment form two helical arrangements, each of which is formed by three support ribs 23.
As a preferred scheme of this embodiment, the reaming blades 22 and the supporting ribs 23 are provided with holes 26, which reduces the weight of the drill bit, and is beneficial to increase the powder discharge space and ensure smooth chip discharge.
The following diameter ratio h (h ═ D) for this example1:D2) Carrying out finite element simulation analysis on the relation with the bit pressure distribution ratio k to obtain a relation formula which is specifically satisfied between the diameter ratio h and the bit pressure distribution ratio k:
as shown in fig. 10, the present embodiment calculates the optimal diameter ratio of the pilot bit 1 and the reamer bit 2 by using a finite element method. In the simulation, the bit pressure distribution ratio of the pilot bit 1 and the reaming bit 2 with different diameter ratios is calculated and analyzed, so that the gauge alloy 4, the reverse alloy 5, the first water hole 14, the second water hole 25, the supporting rib plate 23 and the hole 26 which have no influence on the calculation result are ignored. In the simulation, the crushed rock portions of the pilot blade 12 and the reaming blade 22 are subjected to mesh refinement. The internal equivalent stress of the rock 7 is intensively distributed near the leading edge cloth tooth surface 121 and the reaming edge cloth tooth surface 221, wherein the maximum equivalent stress is intensively distributed in the first arc segment 1212 region of the leading edge cloth tooth surface and the outer cone region of the third arc segment 2212 of the reaming edge cloth tooth surface.
As shown in fig. 11, the diameter ratio h and the bit pressure distribution ratio k are:
h＝D1:D2 (13)
k＝Wexpanding device/(WCollar+WExpanding device) (14)
In the formula: wCollarFor weight-on-bit of pilot bit, WExpanding deviceTo weight the reamer.
As shown in the simulated diameter ratio-bit pressure distribution ratio curve in fig. 11, a polynomial regression is performed on the curve, and the relation between the diameter ratio h and the bit pressure distribution ratio k is obtained as formula (15), where h is-6.78777624401209 k3+8.0441811186145k2-3.73768694982173k+1.29372621712326 (15)。
In order to ensure that the pilot bit 1 and the reaming bit 2 are uniformly worn as much as possible, the bit pressure between the pilot bit 1 and the reaming bit 2 is required to be not greatly different, so that the optimal bit pressure distribution ratio is recommended to be 0.35-0.45. When the bit pressure distribution ratio is between 0.35 and 0.45, the diameter ratio h is calculated to be 0.62 to 0.68 according to the formula (15). Therefore, the optimal diameter ratio h of the present embodiment is 0.62-0.68. At the moment, the energy consumption of rock breaking of the drill bit is greatly reduced.
As shown in fig. 12, it is obtained through simulation that when the diameter ratio of the drill bit is between 0.62 and 0.68, the rock crushing specific work required by the reaming-while-drilling drill bit of the present embodiment to crush the rock of unit volume is significantly reduced, the rock crushing effect of the drill bit is significantly improved, and it is further verified that when the bit pressure distribution ratio is 0.35 to 0.45 and the diameter ratio is 0.62 to 0.68, the rock crushing effect of the reaming-while-drilling drill bit of the present embodiment is the best.
The relationship between the diameter of the first port 14 and the diameter of the second port 25 is analyzed as follows:
when the diameter ratio of the pilot bit 1 to the reaming bit 2 is 0.62-0.68, the crushed rock area ratio A of the pilot bit 1 to the reaming bit 21：A2＝1/4πD1 2：1/4πD2 20.3844 to 0.4624. In order to better carry away the rock dust formed by the broken rock of the pilot bit 1 and the reaming bit 2 from the hole bottom, the distribution of the hydraulic energy of the pilot bit 1 and the reaming bit 2 should be proportional to the broken rock area of the pilot bit 1 and the reaming bit 2, i.e. Q1：Q2＝A1：A2＝0.3844～0.4624。
The hydraulic flow rates of the pilot bit 1 and the reamer bit 2 can be expressed as:
Q1＝a1ν1，Q2＝a2ν2 (16)
in the formula: q1For pilot bit hydraulic flow, Q2For the hydraulic flow of the reaming bit, a1Is the equivalent outlet cross-sectional area of the first port, a2Is the equivalent outlet cross-sectional area of the second water hole, v1Is a first eye equivalent outlet flow rate, v2Is the second port equivalent outlet flow rate.
According to bernoulli's equation, there are:
in the formula: p is a radical of1Is the first eye equivalent outlet pressure, p2And p is the mud density for the second port equivalent outlet pressure.
Let p be1≈p2And is approximately equal to atmospheric pressure, then v1≈ν2。
In general, the diameter of each first port 14 is the same and the diameter of each second port 25 is the same, so that:
in the formula: d1Is the diameter of the first port, n is the number of the first port, d2Is the second port diameter, and m is the second port number.
From this, the diameter d of the first port 14 can be determined1And the diameter d of the second port 252The ratio is in
In the middle, the hydraulic energy distribution of the reaming-while-drilling bit can well lead the rock dust to leave the bottom of the hole.
Claims (11)
1. A large-diameter hole expanding drill bit while drilling in a coal mine is characterized by comprising a pilot drill bit (1) and a hole expanding drill bit (2) which are coaxially connected;
the pilot drill bit (1) comprises a pilot drill bit body (11), a plurality of pilot blades (12) arranged around the circumference of the pilot drill bit body (11), cutting teeth (3) arranged on the cloth tooth surfaces (121) of the pilot blades and gauge-protecting alloy (4) on gauge surfaces (122) of the pilot blades, wherein first chip discharge grooves (13) are formed between the adjacent pilot blades (12), and first water holes (14) are formed in the first chip discharge grooves (13);
the reaming bit (2) comprises a reaming bit body (21), a plurality of reaming blades (22) arranged around the circumference of the reaming bit body (21), supporting rib plates (23) arranged between the adjacent reaming blades (22), cutting teeth (3) arranged on the tooth distribution surface (221) of each reaming blade and gauge-protecting alloy (4) on the gauge surface (222) of each reaming blade, a second chip groove (24) is formed between the adjacent reaming blades (22), and a second water hole (25) is arranged in the second chip groove (24);
the reaming bit body (21) is coaxially connected with the pilot bit body (11); the diameter of the profile formed by one rotation of the outermost tooth of the reaming wing (22) is larger than that of the profile formed by one rotation of the outermost tooth of the pilot wing (12).
2. The large-diameter reaming-while-drilling bit for the underground coal mine according to claim 1, wherein the diameter D of the profile formed by one rotation of the outermost tooth of the pilot blade (12) is the diameter D of the outermost tooth of the pilot blade1The diameter D of a profile formed by one rotation of the outermost teeth of the reaming blades (22)2The ratio h of (a) satisfies the formula (15),
h＝-6.78777624401209k3+8.0441811186145k2-3.73768694982173k+1.29372621712326 (15)
in the equation (15), k is the bit pressure distribution ratio.
3. The large-diameter underground coal mine hole expanding while drilling bit as claimed in claim 2, wherein h is 0.62-0.68.
4. The large-diameter reaming-while-drilling bit for underground coal mines according to any one of claims 1 to 3, wherein the diameter d of the first water hole (14)1And the diameter d of the second port (25)2Has a ratio of
Wherein n is the number of the first water holes (14) and m is the number of the second water holes (25).
5. The large diameter reaming while drilling bit for coal mine wells according to claim 1, characterized in that the reaming blades (22) are detachably connected to the reaming bit body (21).
6. The coal mine underground large-diameter reaming-while-drilling bit according to claim 5, wherein a first positioning groove (211) and a second positioning groove (212) are arranged on the reaming bit body (21), a third positioning groove (224) is arranged on the reaming blade (22), and a bolt hole (225) is arranged at the bottom of the third positioning groove (224); the reaming wing blades (22) are inserted into the first positioning grooves (211), one end of each supporting rib plate (23) is inserted into the second positioning groove (212), two sides of each supporting rib plate (23) are respectively provided with a bulge, the bulges are respectively inserted into the third positioning grooves (224) of the two adjacent reaming wing blades (22), and the bulges are fixed through bolts (6).
7. The large-diameter reaming-while-drilling bit for the underground coal mine according to claim 1 or 6, wherein a plurality of supporting ribs (23) are arranged in a helical line around the reaming bit body (21).
8. The large-diameter underground coal mine hole-expanding while drilling bit as claimed in claim 1 or 6, wherein holes (26) are arranged on the hole-expanding blade (22) and the supporting rib plate (23).
9. The large-diameter reaming-while-drilling bit for the underground coal mine according to claim 1, wherein a cylindrical PDC cutting tooth (31) is arranged in an inner conical region of the leading-hole blade cloth tooth surface (121), an axe-type ridged PDC cutting tooth (32) is arranged in a nose region of the leading-hole blade cloth tooth surface (121), and a triangular ridged PDC cutting tooth (33) is arranged in an outer conical region of the leading-hole blade cloth tooth surface (121).
10. The large-diameter reaming-while-drilling bit for the underground coal mine according to claim 1 or 9, wherein the contour line of the tooth surface (121) of the pilot wing cloth is formed by sequentially and tangentially connecting a first straight line segment (1211), a first circular arc segment (1212) and a second circular arc segment (1213), and the second circular arc segment (1213) is connected with the gauge surface (122) of the pilot wing cloth; the included angle between the first straight line segment (1211) and the vertical direction is 77.5-87.5 degrees, and the distance between the highest point of the contour line of the cloth tooth surface (121) of the pilot cutter wing and the central line of the pilot drill bit (1) is 0.3D1～0.34D1，D1The diameter of a profile formed by one rotation of the outermost tooth of the pilot blade (12).
11. The large-diameter reaming-while-drilling bit for the underground coal mine according to claim 1, wherein the contour line of the tooth distribution surface (221) of the reaming blade is formed by tangentially connecting a second straight line segment (2211) with a third circular arc segment (2212), and the third circular arc segment (2212) is tangentially connected with the gauge surface (222) of the reaming blade; and axe-type ridged PDC cutting teeth (32) and triangular ridged PDC cutting teeth (33) are arranged on the third arc section (2212).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111376456.4A CN114151013B (en) | 2021-11-19 | 2021-11-19 | Underground large-diameter reaming while drilling bit for coal mine |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111376456.4A CN114151013B (en) | 2021-11-19 | 2021-11-19 | Underground large-diameter reaming while drilling bit for coal mine |
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| CN114151013B CN114151013B (en) | 2023-08-11 |
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| CN209308635U (en) * | 2019-01-14 | 2019-08-27 | 成都百施特金刚石钻头有限公司 | PDC drill bit with multiple stage crushing function |
| CN209724230U (en) * | 2019-01-17 | 2019-12-03 | 中国石油化工股份有限公司 | A kind of drill-following reaming bit |
| CN112112575A (en) * | 2020-09-17 | 2020-12-22 | 中煤科工集团西安研究院有限公司 | Garrulous soft coal seam airtight coring bit suitable for ground drilling |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030178232A1 (en) * | 2002-03-25 | 2003-09-25 | Smith International, Inc. | Multi profile performance enhancing concentric drill bit |
| CN202645437U (en) * | 2012-06-13 | 2013-01-02 | 中国石油天然气集团公司 | Device controlling weight on bit relations of reaming while drilling |
| CN103485723A (en) * | 2012-06-13 | 2014-01-01 | 中国石油天然气集团公司 | Device and method for controlling RWD (reaming while drilling) drilling pressure distribution relationship |
| CN105443041A (en) * | 2015-11-17 | 2016-03-30 | 中国石油大学(华东) | Differential pressure type drill |
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| CN106703701A (en) * | 2017-01-20 | 2017-05-24 | 中国石油大学(华东) | Pulse impact producing mechanism and center differential pressure drill comprising same |
| CN209308635U (en) * | 2019-01-14 | 2019-08-27 | 成都百施特金刚石钻头有限公司 | PDC drill bit with multiple stage crushing function |
| CN209724230U (en) * | 2019-01-17 | 2019-12-03 | 中国石油化工股份有限公司 | A kind of drill-following reaming bit |
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| Publication number | Publication date |
|---|---|
| CN114151013B (en) | 2023-08-11 |
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